Semiconductor chip assembly with post/base/post heat spreader

ABSTRACT

A semiconductor chip assembly includes a semiconductor device, a heat spreader, a conductive trace and first and second adhesives. The heat spreader includes a first post, a second post and a base. The conductive trace includes a pad and a terminal. The semiconductor device is electrically connected to the conductive trace and thermally connected to the heat spreader. The first post extends from the base in a first vertical direction into a first opening in the first adhesive, the second post extends from the base in a second vertical direction into a second opening in the second adhesive and the base is sandwiched between and extends laterally from the posts. The conductive trace provides signal routing between the pad and the terminal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.12/616,773 filed Nov. 11, 2009 and a continuation-in-part of U.S.application Ser. No. 12/616,775 filed Nov. 11, 2009, each of which isincorporated by reference. This application also claims the benefit ofU.S. Provisional Application Ser. No. 61/410,932 filed Nov. 7, 2010 andU.S. Provisional Application Ser. No. 61/350,923 filed Jun. 3, 2010,each of which is incorporated by reference.

U.S. application Ser. No. 12/616,773 filed Nov. 11, 2009 and U.S.application Ser. No. 12/616,775 filed Nov. 11, 2009 are each acontinuation-in-part of U.S. application Ser. No. 12/557,540 filed Sep.11, 2009 and a continuation-in-part of U.S. application Ser. No.12/557,541 filed Sep. 11, 2009.

U.S. application Ser. No. 12/557,540 filed Sep. 11, 2009 and U.S.application Ser. No. 12/557,541 filed Sep. 11, 2009 are each acontinuation-in-part of U.S. application Ser. No. 12/406,510 filed Mar.18, 2009, which claims the benefit of U.S. Provisional Application Ser.No. 61/071,589 filed May 7, 2008, U.S. Provisional Application Ser. No.61/071,588 filed May 7, 2008, U.S. Provisional Application Ser. No.61/071,072 filed Apr. 11, 2008, and U.S. Provisional Application Ser.No. 61/064,748 filed Mar. 25, 2008, each of which is incorporated byreference. U.S. application Ser. No. 12/557,540 filed Sep. 11, 2009 andU.S. application Ser. No. 12/557,541 filed Sep. 11, 2009 also claim thebenefit of U.S. Provisional Application Ser. No. 61/150,980 filed Feb.9, 2009, which is incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to semiconductor chip assembly, and moreparticularly to a semiconductor chip assembly with a semiconductordevice, a conductive trace, an adhesive and a heat spreader and itsmethod of manufacture.

2. Description of the Related Art

Semiconductor devices such as packaged and unpackaged semiconductorchips have high voltage, high frequency and high performanceapplications that require substantial power to perform the specifiedfunctions. As the power increases, the semiconductor device generatesmore heat. Furthermore, the heat build-up is aggravated by higherpacking density and smaller profile sizes which reduce the surface areato dissipate the heat.

Semiconductor devices are susceptible to performance degradation as wellas short life span and immediate failure at high operating temperatures.The heat not only degrades the chip, but also imposes thermal stress onthe chip and surrounding elements due to thermal expansion mismatch. Asa result, the heat must be dissipated rapidly and efficiently from thechip to ensure effective and reliable operation. A high thermalconductivity path typically requires heat conduction and heat spreadingto a much larger surface area than the chip or a die pad it is mountedon.

Light emitting diodes (LEDs) have recently become popular alternativesto incandescent, fluorescent and halogen light sources. LEDs provideenergy efficient, cost effective, long term lighting for medical,military, signage, signal, aircraft, maritime, automotive, portable,commercial and residential applications. For instance, LEDs providelight sources for lamps, flashlights, headlights, flood lights, trafficlights and displays.

LEDs include high power chips that generate high light output andconsiderable heat. Unfortunately, LEDs exhibit color shifts and lowlight output as well as short lifetimes and immediate failure at highoperating temperatures. Furthermore, LED light output and reliabilityare constrained by heat dissipation limits. LEDs underscore the criticalneed for providing high power chips with adequate heat dissipation.

LED packages usually include an LED chip, a submount, electricalcontacts and a thermal contact. The submount is thermally connected toand mechanically supports the LED chip. The electrical contacts areelectrically connected to the anode and cathode of the LED chip. Thethermal contact is thermally connected to the LED chip by the submountbut requires adequate heat dissipation by the underlying carrier toprevent the LED chip from overheating.

Packages and thermal boards for high power chips have been developedextensively in the industry with a wide variety of designs andmanufacturing techniques in attempts to meet performance demands in anextremely cost-competitive environment.

Plastic ball grid array (PBGA) packages have a chip and a laminatedsubstrate enclosed in a plastic housing and are attached to a printedcircuit board (PCB) by solder balls. The laminated substrate includes adielectric layer that often includes fiberglass. The heat from the chipflows through the plastic and the dielectric layer to the solder ballsand then the PCB. However, since the plastic and the dielectric layertypically have low thermal conductivity, the PBGA provides poor heatdissipation.

Quad-Flat-No Lead (QFN) packages have the chip mounted on a copper diepad which is soldered to the PCB. The heat from the chip flows throughthe die pad to the PCB. However, since the lead frame type interposerhas limited routing capability, the QFN package cannot accommodate highinput/output (I/O) chips or passive elements.

Thermal boards provide electrical routing, thermal management andmechanical support for semiconductor devices. Thermal boards usuallyinclude a substrate for signal routing, a heat spreader or heat sink forheat removal, pads for electrical connection to the semiconductor deviceand terminals for electrical connection to the next level assembly. Thesubstrate can be a laminated structure with single layer or multi-layerrouting circuitry and one or more dielectric layers. The heat spreadercan be a metal base, a metal slug or an embedded metal layer.

Thermal boards interface with the next level assembly. For instance, thenext level assembly can be a light fixture with a printed circuit boardand a heat sink. In this instance, an LED package is mounted on thethermal board, the thermal board is mounted on the heat sink, thethermal board/heat sink subassembly and the printed circuit board aremounted in the light fixture and the thermal board is electricallyconnected to the printed circuit board by wires. The substrate routeselectrical signals to the LED package from the printed circuit board andthe heat spreader spreads and transfers heat from the LED package to theheat sink. The thermal board thus provides a critical thermal path forthe LED chip.

U.S. Pat. No. 6,507,102 to Juskey et al. discloses an assembly in whicha composite substrate with fiberglass and cured thermosetting resinincludes a central opening, a heat slug with a square or rectangularshape resembling the central opening is attached to the substrate atsidewalls of the central opening, top and bottom conductive layers areattached to the top and bottom of the substrate and electricallyconnected to one another by plated through-holes through the substrate,a chip is mounted on the heat slug and wire bonded to the top conductivelayer, an encapsulant is molded on the chip and solder balls are placedon the bottom conductive layer.

During manufacture, the substrate is initially a prepreg with B-stageresin placed on the bottom conductive layer, the heat slug is insertedinto the central opening and on the bottom conductive layer and spacedfrom the substrate by a gap, the top conductive layer is mounted on thesubstrate, the conductive layers are heated and pressed towards oneanother so that the resin melts, flows into the gap and solidifies, theconductive layers are patterned to form circuit traces on the substrateand expose the excess resin flash on the heat slug, and the excess resinflash is removed to expose the heat slug. The chip is then mounted onthe heat slug, wire bonded and encapsulated.

The heat flows from the chip through the heat slug to the PCB. However,manually dropping the heat slug into the central opening isprohibitively cumbersome and expensive for high volume manufacture.Furthermore, since the heat slug is difficult to accurately position inthe central opening due to tight lateral placement tolerance, voids andinconsistent bond lines arise between the substrate and the heat slug.The substrate is therefore partially attached to the heat slug, fragiledue to inadequate support by the heat slug and prone to delamination. Inaddition, the wet chemical etch that removes portions of the conductivelayers to expose the excess resin flash also removes portions of theheat slug exposed by the excess resin flash. The heat slug is thereforenon-planar and difficult to bond to. As a result, the assembly suffersfrom high yield loss, poor reliability and excessive cost.

U.S. Pat. No. 6,528,882 to Ding et al. discloses a thermal enhanced ballgrid array package in which the substrate includes a metal core layer.The chip is mounted on a die pad region at the top surface of the metalcore layer, an insulating layer is formed on the bottom surface of themetal core layer, blind vias extend through the insulating layer to themetal core layer, thermal balls fill the blind vias and solder balls areplaced on the substrate and aligned with the thermal balls. The heatfrom the chip flows through the metal core layer to the thermal balls tothe PCB. However, the insulating layer sandwiched between the metal corelayer and the PCB limits the heat flow to the PCB.

U.S. Pat. No. 6,670,219 to Lee et al. discloses a cavity down ball gridarray (CDBGA) package in which a ground plate with a central opening ismounted on a heat spreader to form a thermal dissipating substrate. Asubstrate with a central opening is mounted on the ground plate using anadhesive with a central opening. A chip is mounted on the heat spreaderin a cavity defined by the central opening in the ground plate andsolder balls are placed on the substrate. However, since the solderballs extend above the substrate, the heat spreader does not contact thePCB. As a result, the heat spreader releases the heat by thermalconvection rather than thermal conduction which severely limits the heatdissipation.

U.S. Pat. No. 7,038,311 to Woodall et al. discloses a thermal enhancedBGA package in which a heat sink with an inverted T-like shape includesa pedestal and an expanded base, a substrate with a window opening ismounted on the expanded base, an adhesive attaches the pedestal and theexpanded base to the substrate, a chip is mounted on the pedestal andwire bonded to the substrate, an encapsulant is molded on the chip andsolder balls are placed on the substrate. The pedestal extends throughthe window opening, the substrate is supported by the expanded base andthe solder balls are located between the expanded base and the perimeterof the substrate. The heat from the chip flows through the pedestal tothe expanded base to the PCB. However, since the expanded base mustleave room for the solder balls, the expanded base protrudes below thesubstrate only between the central window and the innermost solder ball.Consequently, the substrate is unbalanced and wobbles and warps duringmanufacture. This creates enormous difficulties with chip mounting, wirebonding and encapsulant molding. Furthermore, the expanded base may bebent by the encapsulant molding and may impede soldering the package tothe next level assembly as the solder balls collapse. As a result, thepackage suffers from high yield loss, poor reliability and excessivecost.

U.S. Patent Application Publication No. 2007/0267642 to Erchak et al.discloses a light emitting device assembly in which a base with aninverted T-like shape includes a substrate, a protrusion and aninsulative layer with an aperture, electrical contacts are mounted onthe insulative layer, a package with an aperture and a transparent lidis mounted on the electrical contacts and an LED chip is mounted on theprotrusion and wire bonded to the substrate. The protrusion is adjacentto the substrate and extends through the apertures in the insulativelayer and the package into the package, the insulative layer is mountedon the substrate, the electrical contacts are mounted on the insulativelayer and the package is mounted on the electrical contacts and spacedfrom the insulative layer. The heat from the chip flows through theprotrusion to the substrate to a heat sink. However, the electricalcontacts are difficult to mount on the insulating layer, difficult toelectrically connect to the next level assembly and fail to providemulti-layer routing.

Conventional packages and thermal boards thus have major deficiencies.For instance, dielectrics with low thermal conductivity such as epoxylimit heat dissipation, whereas dielectrics with higher thermalconductivity such as epoxy filled with ceramic or silicon carbide havelow adhesion and are prohibitively expensive for high volumemanufacture. The dielectric may delaminate during manufacture orprematurely during operation due to the heat. The substrate may havesingle layer circuitry with limited routing capability or multi-layercircuitry with thick dielectric layers which reduce heat dissipation.The heat spreader may be inefficient, cumbersome or difficult tothermally connect to the next level assembly. The manufacturing processmay be unsuitable for low cost, high volume manufacture.

In view of the various development stages and limitations in currentlyavailable packages and thermal boards for high power semiconductordevices, there is a need for a semiconductor chip assembly that is costeffective, reliable, manufacturable, versatile, provides flexible signalrouting and has excellent heat spreading and dissipation.

SUMMARY OF THE INVENTION

The present invention provides a semiconductor chip assembly thatincludes a semiconductor device, a heat spreader, a conductive trace andfirst and second adhesives. The heat spreader includes a first post, asecond post and a base. The conductive trace includes a pad and aterminal. The semiconductor device is electrically connected to theconductive trace and thermally connected to the heat spreader. The firstpost extends from the base in a first vertical direction into a firstopening in the first adhesive, the second post extends from the base ina second vertical direction into a second opening in the second adhesiveand the base is sandwiched between and extends laterally from the posts.The conductive trace provides signal routing between the pad and theterminal.

In accordance with an aspect of the present invention, a semiconductorchip assembly includes a semiconductor device, first and secondadhesives, a heat spreader and a conductive trace. The first adhesiveincludes a first opening. The second adhesive includes a second opening.The heat spreader includes a first post, a second post and a base,wherein (i) the first post is adjacent to the base and extendsvertically from the base in a first vertical direction, (ii) the secondpost is adjacent to the base and extends vertically from the base in asecond vertical direction opposite the first vertical direction and(iii) the base is sandwiched between the posts and extends laterallyfrom the posts in lateral directions orthogonal to the verticaldirections. The conductive trace includes a pad, a terminal and anelectrical interconnect, wherein an electrically conductive path betweenthe pad and the terminal includes the electrical interconnect.

The semiconductor device is mounted on the first post, extendsvertically beyond the base in the first vertical direction, extendslaterally within peripheries of the posts, is electrically connected tothe pad and thereby electrically connected to the terminal and isthermally connected to the first post and thereby thermally connected tothe second post. The first adhesive extends vertically beyond the basein the first vertical direction, extends laterally from the first postto or beyond the terminal and is sandwiched between the base and thepad. The second adhesive extends vertically beyond the base in thesecond vertical direction, extends laterally from the second post to orbeyond the terminal and is sandwiched between the base and the terminal.The pad extends vertically beyond the base in the first verticaldirection, the terminal extends vertically beyond the base in the secondvertical direction and the electrical interconnect extends through theadhesives and the base and is spaced from and electrically isolated fromthe base. The first post extends into the first opening, the second postextends into the second opening and the base is sandwiched between theadhesives and covers the semiconductor device in the second verticaldirection.

In accordance with another aspect of the present invention, asemiconductor chip assembly includes a semiconductor device, first andsecond adhesives, a heat spreader and a conductive trace. The firstadhesive includes a first opening. The second adhesive includes a secondopening. The heat spreader includes a first post, a second post, a firstcap, a second cap and a base, wherein (i) the first post is adjacent toand integral with the base, extends vertically from the base in a firstvertical direction and is sandwiched between the base and the first cap,(ii) the second post is adjacent to and integral with the base, extendsvertically from the base in a second vertical direction opposite thefirst vertical direction and is sandwiched between the base and thesecond cap, (iii) the base is sandwiched between the posts and extendslaterally from the posts in lateral directions orthogonal to thevertical directions, (iv) the first cap is adjacent to the first post,covers the first post in the first vertical direction and extendslaterally from the first post and (v) the second cap is adjacent to thesecond post, covers the second post in the second vertical direction andextends laterally from the second post. The conductive trace includes apad, a terminal and an electrical interconnect, wherein an electricallyconductive path between the pad and the terminal includes the electricalinterconnect.

The semiconductor device is mounted on the first cap, extends verticallybeyond the first cap in the first vertical direction, extends laterallywithin peripheries of the posts and the caps, is electrically connectedto the pad and thereby electrically connected to the terminal and isthermally connected to the first cap and thereby thermally connected tothe second cap. The first adhesive contacts the first post and the base,is spaced from the second post, extends vertically beyond the base inthe first vertical direction, extends laterally from the first post toor beyond the terminal and is sandwiched between the base and the pad.The second adhesive contacts the second post and the base, is spacedfrom the first post, extends vertically beyond the base in the secondvertical direction, extends laterally from the second post to or beyondthe terminal and is sandwiched between the base and the terminal. Thepad extends vertically beyond the first adhesive in the first verticaldirection, the terminal extends vertically beyond the second adhesive inthe second vertical direction and the electrical interconnect extendsthrough the adhesives and the base and is spaced from and electricallyisolated from the base. The first post extends into the first opening,the second post extends into the second opening, the first cap extendsvertically beyond the first adhesive in the first vertical direction,the second cap extends vertically beyond the second adhesive in thesecond vertical direction and the base is sandwiched between theadhesives and covers the semiconductor device in the second verticaldirection.

The first cap can have a rectangular or square shape and the first postcan have a circular shape. In this instance, the first cap can be sizedand shaped to accommodate a thermal contact surface of the semiconductordevice whereas the first post is not sized and shaped to accommodate thethermal contact surface of the semiconductor device. Likewise, thesecond cap can have a rectangular or square shape and the second postcan have a circular shape. In this instance, the second cap can be sizedand shaped to accommodate a thermal contact surface of a heat sinkwhereas the second post is not sized and shaped to accommodate thethermal contact surface of the heat sink. In any case, the caps arethermally connected to one another by the posts and the base.

The heat spreader can consist of the posts and the base or the posts,the base and the caps. The heat spreader can also consist essentially ofcopper, aluminum or copper/nickel/aluminum. The heat spreader can alsoconsist of a buried copper, aluminum or copper/nickel/aluminum coreshared by the posts and the base and plated surface contacts thatconsist of gold, silver and/or nickel at the caps. In any case, the heatspreader provides heat dissipation and spreading from the semiconductordevice to the next level assembly.

The semiconductor device can be mounted on the heat spreader and theconductive trace. For instance, the semiconductor device can be mountedon the first cap and the pad, extend beyond the first cap and the pad inthe first vertical direction, be electrically connected to the pad usinga first solder joint and be thermally connected to the heat spreaderusing a second solder joint. Alternatively, the semiconductor device canbe mounted on the first cap but not the pad, extend beyond the first capand the pad in the first vertical direction, be electrically connectedto the pad using a wire bond and be thermally connected to the first capusing a die attach.

The semiconductor device can be a packaged or unpackaged semiconductorchip. For instance, the semiconductor device can be an LED package thatincludes an LED chip, is mounted on the first cap and the pad, extendsbeyond the first cap and the pad in the first vertical direction, iselectrically connected to the pad using a first solder joint and isthermally connected to the first cap using a second solder joint.Alternatively, the semiconductor device can be a semiconductor chip suchas an LED chip that is mounted on the first cap but not the pad, extendsbeyond the first cap and the pad in the first vertical direction, iselectrically connected to the pad using a wire bond and is thermallyconnected to the first cap using a die attach.

The first adhesive can contact the first post, the first cap and thebase and be spaced from the second post, the second adhesive, theelectrical interconnect and the terminal. The first adhesive can alsocontact and be sandwiched between the first post and the pad, betweenthe base and the pad and between the base and the first cap. The firstadhesive can also cover and surround the first post in the lateraldirections, cover the base outside the first post in the first verticaldirection and cover the first cap outside the first post in the secondvertical direction. The first adhesive can also conformally coat thesidewalls of the first post.

The first adhesive can extend laterally from the first post to or beyondthe terminal. For instance, the first adhesive and the terminal canextend to peripheral edges of the assembly. In this instance, the firstadhesive extends laterally from the first post to the terminal.Alternatively, the first adhesive can extend to peripheral edges of theassembly and the terminal can be spaced from the peripheral edges of theassembly. In this instance, the first adhesive extends laterally fromthe first post beyond the terminal.

The first adhesive alone can intersect an imaginary horizontal linebetween the first post and an insulative filler, an imaginary horizontalline between the first post and a peripheral edge of the assembly, animaginary vertical line between the base and the pad and an imaginaryvertical line between the base and the first cap.

The second adhesive can contact the second post, the second cap and thebase and be spaced from the first post, the first adhesive, theelectrical interconnect and the pad. The second adhesive can alsocontact and be sandwiched between the second post and the terminal,between the base and the terminal and between the base and the secondcap. The second adhesive can also cover and surround the second post inthe lateral directions, cover the base outside the second post in thesecond vertical direction and cover the second cap outside the secondpost in the first vertical direction. The second adhesive can alsoconformally coat the sidewalls of the second post.

The second adhesive can extend laterally from the second post to orbeyond the terminal. For instance, the second adhesive and the terminalcan extend to peripheral edges of the assembly. In this instance, thesecond adhesive extends laterally from the second post to the terminal.Alternatively, the second adhesive can extend to peripheral edges of theassembly and the terminal can be spaced from the peripheral edges of theassembly. In this instance, the second adhesive extends laterally fromthe second post beyond the terminal.

The second adhesive alone can intersect an imaginary horizontal linebetween the second post and an insulative filler, an imaginaryhorizontal line between the second post and a peripheral edge of theassembly, an imaginary vertical line between the base and the terminaland an imaginary vertical line between the base and the second cap.

The posts can be integral with the base. For instance, the posts and thebase can be a single-piece metal or include a single-piece metal attheir interface, and the single-piece metal can be copper. The firstpost can be coplanar with the first adhesive at the first cap and at thebase and second post can also be coplanar with the second adhesive atthe second cap and at the base. The first post can also have a cut-offconical or pyramidal shape in which its diameter decreases as it extendsin the first vertical direction from the base to the first cap and thesecond post can also have a cut-off conical or pyramidal shape in whichits diameter decreases as it extends in the second vertical directionfrom the base to the second cap.

The base can cover the first post and the first adhesive in the secondvertical direction, cover the second post and the second adhesive in thefirst vertical direction, support the posts and the adhesives and extendto peripheral edges of the assembly. The base can also be thicker thanthe pad, the terminal and the caps.

The pad can contact or be spaced from the first adhesive and theterminal can contact or be spaced from the second adhesive. Forinstance, the pad can contact the first adhesive and the terminal cancontact the second adhesive. Alternatively, the assembly can includefirst and second dielectric layers, wherein the pad is spaced from thefirst adhesive, the terminal is spaced from the second adhesive, thefirst dielectric layer contacts and is sandwiched between the pad andthe first adhesive and is spaced from the first post and the base, thesecond dielectric layer contacts and is sandwiched between the terminaland the second adhesive and is spaced from the second post and the base,the dielectric layers are spaced from one another and the electricalinterconnect extends through the dielectric layers. Furthermore, a firstsubstrate can include the pad and the first dielectric layer and be alaminated structure that is spaced from the first post and the base anda second substrate can include the terminal and the second dielectriclayer and be a laminated structure that is spaced from the second postand the base.

The pad and the first cap can have the same thickness where closest toone another, have different thickness where the first cap is adjacent tothe first post and be coplanar with one another at a surface that facesin the first vertical direction.

The terminal and the second cap can have the same thickness whereclosest to one another, have different thickness where the second cap isadjacent to the second post and be coplanar with one another at asurface that faces in the second vertical direction.

The conductive trace can include a routing line that extends beyond thefirst adhesive in the first vertical direction and extends laterally inan electrically conductive path between the pad and the electricalinterconnect. Likewise, the conductive trace can include a routing linethat extends beyond the second adhesive in the second vertical directionand extends laterally in an electrically conductive path between theterminal and the electrical interconnect. Furthermore, the electricalinterconnect can be a plated through-hole that extends through and isspaced from the base and the adhesives and is located within aninsulative filler that contacts and extends through the base and theadhesives.

The conductive trace can consist essentially of copper. The conductivetrace can also include a buried copper core shared by the pad, theterminal and the electrical interconnect and plated surface contactsthat consist of gold, silver and/or nickel at the pad and the terminal.In any case, the conductive trace provides signal routing between thepad and the terminal.

The pad can be an electrical contact for the semiconductor device, theterminal can be an electrical contact for the next level assembly, andthe pad and the terminal can provide signal routing between thesemiconductor device and the next level assembly.

The pad, the terminal and the caps can be the same metals and the postsand the base can be the same metal. For instance, the pad, the terminaland the caps can include a gold, silver or nickel surface layer and aburied copper core and be primarily copper, the posts and the base canbe copper and the electrical interconnect can include copper. In thisinstance, a plated contact can include a gold or silver surface layerand a buried nickel layer that contacts and is sandwiched between thesurface layer and the buried copper core or a nickel surface layer thatcontacts the buried copper core.

The heat spreader can include a copper core shared by the posts, thebase and the caps and the conductive trace can include a copper coreshared by the pad, the terminal and the electrical interconnect. Forinstance, the heat spreader can include a gold, silver or nickel surfacelayer at the caps, a buried copper core at the posts, the base and thecaps and be primarily copper. In this instance, the first cap caninclude a plated contact as its surface layer and the second cap caninclude a plated contact as its surface layer. Likewise, the conductivetrace can include a gold, silver or nickel surface layer at the pad andthe terminal, a buried copper core at the pad, the terminal and theelectrical interconnect and be primarily copper. In this instance, thepad can include a plated contact as its surface layer and the terminalcan include a plated contact as its surface layer.

The assembly can be a first-level or second-level single-chip ormulti-chip device. For instance, the assembly can be a first-levelpackage that contains a single chip or multiple chips. Alternatively,the assembly can be a second-level module that contains a single LEDpackage or multiple LED packages, and each LED package can contain asingle LED chip or multiple LED chips.

The present invention provides a method of making a semiconductor chipassembly that includes providing first and second posts, first andsecond adhesives and a base, wherein the first post extends from thebase in a first vertical direction into a first opening in the firstadhesive, the second post extends from the base in a second verticaldirection into a second opening in the second adhesive and the base issandwiched between and extends laterally from the posts, then flowingthe first adhesive in the first vertical direction and the secondadhesive in the second vertical direction, solidifying the adhesives,then providing a conductive trace that includes a pad and a terminal,wherein the pad extends beyond the base in the first vertical directionand the terminal extends beyond the base in the second verticaldirection, providing a heat spreader that includes the posts and thebase, then mounting a semiconductor device on the first post,electrically connecting the semiconductor device to the conductive traceand thermally connecting the semiconductor device to the heat spreader.

In accordance with an aspect of the present invention, a method ofmaking a semiconductor chip assembly includes (1) providing a firstpost, a second post, a first adhesive, a second adhesive and a base,wherein (a) the first post is adjacent to the base, extends verticallyfrom the base in a first vertical direction and extends into a firstopening in the first adhesive, (b) the second post is adjacent to thebase, extends vertically from the base in a second vertical directionopposite the first vertical direction and extends into a second openingin the second adhesive, (c) the first adhesive contacts the base,extends vertically beyond the base in the first vertical direction andis non-solidified, (d) the second adhesive contacts the base, extendsvertically beyond the base in the second vertical direction and isnon-solidified, and (e) the base is sandwiched between the posts andbetween the adhesives and extends laterally from the posts in lateraldirections orthogonal to the vertical directions, then (2) flowing thefirst adhesive, (3) flowing the second adhesive, (4) solidifying theadhesives, then (5) providing a conductive trace that includes a pad, aterminal and an electrical interconnect, wherein the pad extendsvertically beyond the base in the first vertical direction, the terminalextends vertically beyond the base in the second vertical direction, theelectrical interconnect extends through the adhesives and the base andis spaced from and electrically isolated from the base and anelectrically conductive path between the pad and the terminal includesthe electrical interconnect, (6) providing a heat spreader that includesthe posts and the base, then (7) mounting a semiconductor device on thefirst post, wherein the semiconductor device extends vertically beyondthe base in the first vertical direction, extends laterally intoperipheries of the posts and the first post is sandwiched between thesemiconductor device and the base, (8) electrically connecting thesemiconductor device to the pad, thereby electrically connecting thesemiconductor device to the terminal, and (9) thermally connecting thesemiconductor device to the first post, thereby thermally connecting thesemiconductor device to the second post.

Providing the conductive trace can providing selected portions of firstand second conductive layers. Furthermore, the conductive layers can beprovided before or after solidifying the adhesives.

For instance, the method can include contacting a first release sheetand the first adhesive, wherein the first adhesive contacts and issandwiched between the first release sheet and the base, then flowingand solidifying the first adhesive, then removing the first releasesheet from the first adhesive, then depositing a first conductive layeron the first adhesive and then providing the conductive trace with aselected portion of the first conductive layer. Likewise, the method caninclude contacting a second release sheet and the second adhesive,wherein the second adhesive contacts and is sandwiched between thesecond release sheet and the base, then flowing and solidifying thesecond adhesive, then removing the second release sheet from the secondadhesive, then depositing a second conductive layer on the secondadhesive and then providing the conductive trace with a selected portionof the second conductive layer. As a result, the first adhesivelaminates only itself to the first post and the base, the secondadhesive laminates only itself to the second post and the base and theconductive layers are provided after solidifying the adhesives.Furthermore, the conductive layers can be deposited by sputtering andthen electroplating or by electroless plating and then electroplating.

As another example, the method can include providing a first conductivelayer, then flowing the first adhesive into a first aperture thatextends through the first conductive layer and then providing theconductive trace with a selected portion of the first conductive layer.Likewise, the method can include providing a second conductive layer,then flowing the second adhesive into a second aperture that extendsthrough the second conductive layer and then providing the conductivetrace with a selected portion of the second conductive layer. In thismanner, the first adhesive laminates the first conductive layer to thefirst post and the base, the second adhesive laminates the secondconductive layer to the second post and the base and the conductivelayers are provided before solidifying the adhesives.

In accordance with another aspect of the present invention, a method ofmaking a semiconductor chip assembly includes (1) providing a firstpost, a second post, a first adhesive, a second adhesive, a firstconductive layer, a second conductive layer and a base, wherein (a) thefirst post is adjacent to and integral with the base, extends verticallyfrom the base in a first vertical direction, extends into a firstopening in the first adhesive and is aligned with a first aperture inthe first conductive layer, (b) the second post is adjacent to andintegral with the base, extends vertically from the base in a secondvertical direction opposite the first vertical direction, extends into asecond opening in the second adhesive and is aligned with a secondaperture in the second conductive layer, (c) the first adhesive contactsthe base, is sandwiched between the base and the first conductive layer,extends vertically beyond the base in the first vertical direction andis non-solidified, (d) the second adhesive contacts the base, issandwiched between the base and the second conductive layer, extendsvertically beyond the base in the second vertical direction and isnon-solidified, (e) the first conductive layer extends vertically beyondthe first adhesive in the first vertical direction, (f) the secondconductive layer extends vertically beyond the second adhesive in thesecond vertical direction, and (g) the base is sandwiched between theposts, between the adhesives and between the conductive layers andextends laterally from the posts in lateral directions orthogonal to thevertical directions, then (2) flowing the first adhesive in the firstvertical direction into a first gap located in the first aperturebetween the first post and the first conductive layer, (3) flowing thesecond adhesive in the second vertical direction into a second gaplocated in the second aperture between the second post and the secondconductive layer, (4) solidifying the adhesives, thereby mechanicallyattaching the first conductive layer to the first post and the baseusing the first adhesive and mechanically attaching the secondconductive layer to the second post and the base using the secondadhesive, then (5) providing a conductive trace that includes a pad, aterminal, an electrical interconnect and selected portions of theconductive layers, wherein the pad extends vertically beyond the base inthe first vertical direction, the terminal extends vertically beyond thebase in the second vertical direction, the electrical interconnectextends through the adhesives and the base and is spaced from andelectrically isolated from the base and an electrically conductive pathbetween the pad and the terminal includes the electrical interconnect,(6) providing a heat spreader that includes the posts and the base, then(7) mounting a semiconductor device on the first post, wherein thesemiconductor device extends vertically beyond the base in the firstvertical direction, extends laterally within peripheries of the postsand the first post is sandwiched between the semiconductor device andthe base, (8) electrically connecting the semiconductor device to thepad, thereby electrically connecting the semiconductor device to theterminal, and (9) thermally connecting the semiconductor device to thefirst post, thereby thermally connecting the semiconductor device to thesecond post.

Providing the first conductive layer can include mounting the firstconductive layer alone on the first adhesive, or alternatively,attaching the first conductive layer to a first carrier, then mountingthe first conductive layer and the first carrier on the first adhesivesuch that the first conductive layer contacts and is sandwiched betweenthe first adhesive and the first carrier, and then, after solidifyingthe first adhesive, removing the first carrier and then providing theconductive trace. As another alternative, mounting the first conductivelayer can include mounting the first conductive layer and a firstdielectric layer on the first adhesive such that the first dielectriclayer contacts and is sandwiched between the first conductive layer andthe first adhesive.

Providing the second conductive layer can include mounting the secondconductive layer alone on the second adhesive, or alternatively,attaching the second conductive layer to a second carrier, then mountingthe second conductive layer and the second carrier on the secondadhesive such that the second conductive layer contacts and issandwiched between the second adhesive and the second carrier, and then,after solidifying the second adhesive, removing the second carrier andthen providing the conductive trace. As another alternative, mountingthe second conductive layer can include mounting the second conductivelayer and a second dielectric layer on the second adhesive such that thesecond dielectric layer contacts and is sandwiched between the secondconductive layer and the second adhesive.

In accordance with another aspect of the present invention, a method ofmaking a semiconductor chip assembly includes (1) providing a firstpost, a second post, a first adhesive, a second adhesive, a firstconductive layer, a second conductive layer and a base, wherein (a) thefirst post is adjacent to and integral with the base, extends verticallyfrom the base in a first vertical direction, extends into a firstopening in the first adhesive and is aligned with a first aperture inthe first conductive layer, (b) the second post is adjacent to andintegral with the base, extends vertically from the base in a secondvertical direction opposite the first vertical direction, extends into asecond opening in the second adhesive and is aligned with a secondaperture in the second conductive layer, (c) the first adhesive contactsthe base, is sandwiched between the base and the first conductive layer,extends vertically beyond the base in the first vertical direction andis non-solidified, (d) the second adhesive contacts the base, issandwiched between the base and the second conductive layer, extendsvertically beyond the base in the second vertical direction and isnon-solidified, (e) the first conductive layer extends vertically beyondthe first adhesive in the first vertical direction, (f) the secondconductive layer extends vertically beyond the second adhesive in thesecond vertical direction, and (g) the base is sandwiched between theposts, between the adhesives and between the conductive layers andextends laterally from the posts in lateral directions orthogonal to thevertical directions, then (2) flowing the first adhesive in the firstvertical direction into a first gap located in the first aperturebetween the first post and the first conductive layer, (3) flowing thesecond adhesive in the second vertical direction into a second gaplocated in the second aperture between the second post and the secondconductive layer, (4) solidifying the adhesives, thereby mechanicallyattaching the first conductive layer to the first post and the baseusing the first adhesive and mechanically attaching the secondconductive layer to the second post and the base using the secondadhesive, then (5) providing a conductive trace that includes a pad, aterminal, an electrical interconnect and selected portions of theconductive layers, wherein the pad extends vertically beyond the firstadhesive in the first vertical direction, the terminal extendsvertically beyond the second adhesive in the second vertical direction,the electrical interconnect extends through the adhesives and the baseand is spaced from and electrically isolated from the base and anelectrically conductive path between the pad and the terminal includesthe electrical interconnect, (6) providing a heat spreader that includesthe posts, the base, a first cap, a second cap and selected portions ofthe conductive layers, wherein the first cap is adjacent to the firstpost, covers the first post in the first vertical direction, extendslaterally from the first post and extends vertically beyond the firstadhesive in the first vertical direction and the second cap is adjacentto the second post, covers the second post in the second verticaldirection, extends laterally from the second post and extends verticallybeyond the second adhesive in the second vertical direction, then (7)mounting a semiconductor device on the first cap, wherein thesemiconductor device extends vertically beyond the first cap in thefirst vertical direction and extends laterally within peripheries of theposts and the caps and the first post and the first cap are sandwichedbetween the semiconductor device and the base, (8) electricallyconnecting the semiconductor device to the pad, thereby electricallyconnecting the semiconductor device to the terminal, and (9) thermallyconnecting the semiconductor device to the first cap, thereby thermallyconnecting the semiconductor device to the second cap.

In accordance with another aspect of the present invention, a method ofmaking a semiconductor chip assembly includes (1) providing a firstpost, a second post, a first adhesive, a second adhesive, a firstconductive layer, a second conductive layer and a base, wherein (a) thefirst post is adjacent to and integral with the base, extends verticallyfrom the base in a first vertical direction, extends into a firstopening in the first adhesive and is aligned with a first aperture inthe first conductive layer, (b) the second post is adjacent to andintegral with the base, extends vertically from the base in a secondvertical direction opposite the first vertical direction, extends into asecond opening in the second adhesive and is aligned with a secondaperture in the second conductive layer, (c) the first adhesive contactsthe base, is sandwiched between the base and the first conductive layer,extends vertically beyond the base in the first vertical direction andis non-solidified, (d) the second adhesive contacts the base, issandwiched between the base and the second conductive layer, extendsvertically beyond the base in the second vertical direction and isnon-solidified, (e) the first conductive layer extends vertically beyondthe first adhesive in the first vertical direction, (f) the secondconductive layer extends vertically beyond the second adhesive in thesecond vertical direction, and (g) the base is sandwiched between theposts, between the adhesives and between the conductive layers andextends laterally from the posts in lateral directions orthogonal to thevertical directions, then (2) applying heat to melt the adhesives, (3)moving the conductive layers towards one another, thereby (a) moving thefirst post in the first vertical direction in the first aperture, (b)moving the second post in the second vertical direction in the secondaperture, (c) applying pressure to the molten first adhesive between thebase and the first conductive layer and (d) applying pressure to themolten second adhesive between the base and the second conductive layer,wherein (e) the pressure between the base and the first conductive layerforces the molten first adhesive to flow in the first vertical directioninto a first gap located in the first aperture between the first postand the first conductive layer and (f) the pressure between the base andthe second conductive layer forces the molten second adhesive to flow inthe second vertical direction into a second gap located in the secondaperture between the second post and the second conductive layer, (4)applying heat to solidify the molten adhesives, thereby mechanicallyattaching the first conductive layer to the first post and the baseusing the first adhesive and mechanically attaching the secondconductive layer to the second post and the base using the secondadhesive, then (5) providing a conductive trace that includes a pad, aterminal and an electrical interconnect, wherein the pad includes aselected portion of the first conductive layer and extends verticallybeyond the first adhesive in the first vertical direction, the terminalincludes a selected portion of the second conductive layer and extendsvertically beyond the second adhesive in the second vertical direction,the electrical interconnect extends through the adhesives and the baseand is spaced from and electrically isolated from the base and anelectrically conductive path between the pad and the terminal includesthe electrical interconnect, (6) providing a heat spreader that includesthe posts, the base, a first cap and a second cap, wherein the first capis adjacent to the first post, covers the first post in the firstvertical direction, extends laterally from the first post, extendsvertically beyond the first adhesive in the first vertical direction andincludes a selected portion of the first conductive layer and the secondcap is adjacent to the second post, covers the second post in the secondvertical direction, extends laterally from the second post, extendsvertically beyond the second adhesive in the second vertical directionand includes a selected portion of the second conductive layer, then (7)mounting a semiconductor device on the first cap, wherein thesemiconductor device extends vertically beyond the first cap in thefirst vertical direction and extends laterally within peripheries of theposts and the caps and the first post and the first cap are sandwichedbetween the semiconductor device and the base, (8) electricallyconnecting the semiconductor device to the pad, thereby electricallyconnecting the semiconductor device to the terminal, and (9) thermallyconnecting the semiconductor device to the first cap, thereby thermallyconnecting the semiconductor device to the second cap.

Providing the posts and the base can include providing a metal plate,forming a first etch mask on the metal plate that selectively exposesthe metal plate in the first vertical direction and defines the firstpost, forming a second etch mask on the metal plate that selectivelyexposes the metal plate in the second vertical direction and defines thesecond post, then etching the metal plate in a first pattern defined bythe first etch mask and a second pattern defined by the second etchmask, thereby forming a first recess in the metal plate that extendsinto but not through the metal plate and a second recess in the metalplate that extends into but not through the metal plate, wherein thefirst post includes an unetched portion of the metal plate thatprotrudes beyond the base in the first vertical direction and islaterally surrounded by the first recess, the second post includes anunetched portion of the metal plate that protrudes beyond the base inthe second vertical direction and is laterally surrounded by the secondrecess and the base includes an unetched portion of the metal plate thatis sandwiched between the posts and between the recesses, and thenremoving the etch masks.

Providing the first adhesive can include providing a first prepreg witha first uncured epoxy and then inserting the first post into the firstopening, flowing the first adhesive can include melting the firstuncured epoxy and compressing the first uncured epoxy between the firstconductive layer and the base and solidifying the first adhesive caninclude curing the molten first uncured epoxy. Likewise, providing thesecond adhesive can include providing a second prepreg with a seconduncured epoxy and then inserting the second post into the secondopening, flowing the second adhesive can include melting the seconduncured epoxy and compressing the second uncured epoxy between thesecond conductive layer and the base and solidifying the second adhesivecan include curing the molten second uncured epoxy.

Providing the first conductive layer can include contacting the firstconductive layer and the first adhesive, wherein the first apertureextends through the first conductive layer alone, and then flowing thefirst adhesive into the first gap. Likewise, providing the secondconductive layer can include contacting the second conductive layer andthe second adhesive, wherein the second aperture extends through thesecond conductive layer alone, and then flowing the second adhesive intothe second gap. In this manner, the first adhesive laminates the firstconductive layer alone to the first post and the base and the secondadhesive laminates the second conductive layer alone to the second postand the base.

Providing the first conductive layer can include providing a firstsubstrate that includes the first conductive layer and a firstdielectric layer and then contacting the first dielectric layer and thefirst adhesive, wherein the first dielectric layer contacts and issandwiched between the first conductive layer and the first adhesive andis solidified and the first aperture extends through the firstconductive layer and the first dielectric layer, and then flowing thefirst adhesive into the first gap. Likewise, providing the secondconductive layer can include providing a second substrate that includesthe second conductive layer and a second dielectric layer and thencontacting the second dielectric layer and the second adhesive, whereinthe second dielectric layer contacts and is sandwiched between thesecond conductive layer and the second adhesive and is solidified andthe second aperture extends through the second conductive layer and thesecond dielectric layer, and then flowing the second adhesive into thesecond gap. In this manner, the first adhesive laminates the firstconductive layer and the first dielectric layer to the first post andthe base and the second adhesive laminates the second conductive layerand the second dielectric layer to the second post and the base.

Providing the pad can include removing selected portions of the firstconductive layer after solidifying the first adhesive. The removing caninclude applying a wet chemical etch to the first conductive layer usingan etch mask that defines the pad such that the pad includes a selectedportion of the first conductive layer.

Providing the terminal can include removing selected portions of thesecond conductive layer after solidifying the second adhesive. Theremoving can include applying a wet chemical etch to the secondconductive layer using an etch mask that defines the terminal such thatthe terminal includes a selected portion of the second conductive layer.

Providing the first cap can include removing selected portions of thefirst conductive layer after solidifying the first adhesive. Theremoving can include applying a wet chemical etch to the firstconductive layer using an etch mask that defines the first cap such thatthe first cap includes a selected portion of the first conductive layer.

Providing the second cap can include removing selected portions of thesecond conductive layer after solidifying the second adhesive. Theremoving can include applying a wet chemical etch to the secondconductive layer using an etch mask that defines the second cap suchthat the second cap includes a selected portion of the second conductivelayer.

Providing the pad and the first cap can include removing selectedportions of the first conductive layer using an etch mask that definesthe pad and the first cap. Thus, the pad and the first cap can be formedsimultaneously using the same etch mask and wet chemical etch.

Providing the terminal and the second cap can include removing selectedportions of the second conductive layer using an etch mask that definesthe terminal and the second cap. Thus, the terminal and the second capcan be formed simultaneously using the same etch mask and wet chemicaletch.

Providing the pad and the first cap can include grinding the first post,the first adhesive and the first conductive layer after solidifying thefirst adhesive such that the first post, the first adhesive and thefirst conductive layer are laterally aligned with one another at alateral surface that faces in the first vertical direction, and thenremoving selected portions of the first conductive layer such that thepad and the first cap include selected portions of the first conductivelayer. The grinding can include grinding the first adhesive withoutgrinding the first post and then grinding the first post, the firstadhesive and the first conductive layer. The removing can includeapplying a wet chemical etch to the first conductive layer using an etchmask that defines the pad and the first cap.

Providing the terminal and the second cap can include grinding thesecond post, the second adhesive and the second conductive layer aftersolidifying the second adhesive such that the second post, the secondadhesive and the second conductive layer are laterally aligned with oneanother at a lateral surface that faces in the second verticaldirection, and then removing selected portions of the second conductivelayer such that the terminal and the second cap include selectedportions of the second conductive layer. The grinding can includegrinding the second adhesive without grinding the second post and thengrinding the second post, the second adhesive and the second conductivelayer. The removing can include applying a wet chemical etch to thesecond conductive layer using an etch mask that defines the terminal andthe second cap.

Providing the pad and the first cap can include depositing a firstplated layer on the first post, the first adhesive and the firstconductive layer after the grinding and then removing selected portionsof the first conductive layer and the first plated layer such that thepad and the first cap include selected portions of the first conductivelayer and the first plated layer. Depositing the first plated layer caninclude electrolessly plating an electrolessly plated layer on the firstpost, the first adhesive and the first conductive layer and thenelectroplating an electroplated layer on the electrolessly plated layer.The removing can include applying the wet chemical etch to the firstconductive layer and the first plated layer using the etch mask todefine the pad and the first cap.

Providing the terminal and the second cap can include depositing asecond plated layer on the second post, the second adhesive and thesecond conductive layer after the grinding and then removing selectedportions of the second conductive layer and the second plated layer suchthat the terminal and the second cap include selected portions of thesecond conductive layer and the second plated layer. Depositing thesecond plated layer can include electrolessly plating an electrolesslyplated layer on the second post, the second adhesive and the secondconductive layer and then electroplating an electroplated layer on theelectroles sly plated layer. The removing can include applying the wetchemical etch to the second conductive layer and the second plated layerusing the etch mask to define the terminal and the second cap.

Providing the conductive trace can include providing a hole that extendsthrough the base, the adhesives and the conductive layers aftersolidifying the adhesives, then depositing a plated metal on the posts,the adhesives and the conductive layers, wherein the plated metal formsa first plated layer that covers the first post in the first verticaldirection, a second plated layer that covers the second post in thesecond vertical direction and the electrical interconnect as a platedthrough-hole in the hole, then forming a first etch mask on the firstplated layer that defines the pad, forming a second etch mask on thesecond plated layer that defines the terminal, then etching the firstconductive layer and the first plated layer in a first pattern definedby the first etch mask and etching the second conductive layer and thesecond plated layer in a second pattern defined by the second etch maskand then removing the etch masks.

Providing the hole can include providing an inner hole that extendsthrough and is coaxial with an outer hole. For instance, providing thehole can include forming an outer hole that extends through and isadjacent to the base, the adhesives and the conductive layers aftersolidifying the adhesives, then depositing an insulative filler into theouter hole, and then forming the inner hole that extends through theouter hole, extends through and is adjacent to the insulative filler,extends through and is spaced from the base, the adhesives and theconductive layers and provides the hole. Furthermore, the inner hole canbe formed in a single step by mechanical drilling, laser drilling orplasma etching and the outer hole can be formed in a single step bymechanical drilling or laser drilling or multiple steps in which thebase, the first conductive layer and/or the second conductive layer areopened by wet chemical etching and the adhesives are opened by laserdrilling or plasma etching.

Etching the first conductive layer and the first plated layer caninclude exposing the first adhesive in the first vertical directionwithout exposing the second adhesive in the first vertical direction,and etching the second conductive layer and the second plated layer caninclude exposing the second adhesive in the second vertical directionwithout exposing the first adhesive in the second vertical direction.

The pad can be formed before, during or after the terminal is formed.Thus, the pad and the terminal can be formed simultaneously using thesame wet chemical etch and different etch masks or sequentially usingdifferent etch masks. Likewise, the first cap can be formed before,during or after the second cap is formed. Thus, the caps can be formedsimultaneously using the same wet chemical etch and different etch masksor sequentially using different etch masks. Similarly, the pad, theterminal and the caps can be formed simultaneously or sequentially.

Flowing the first adhesive can include filling the first gap with thefirst adhesive. Flowing the first adhesive can also include squeezingthe first adhesive through the first gap, beyond the first post and thefirst conductive layer in the first vertical direction and on surfaceportions of the first post and the first conductive layer adjacent tothe first gap that face in the first vertical direction.

Flowing the second adhesive can include filling the second gap with thesecond adhesive. Flowing the second adhesive can also include squeezingthe second adhesive through the second gap, beyond the second post andthe second conductive layer in the second vertical direction and onsurface portions of the second post and the second conductive layeradjacent to the second gap that face in the second vertical direction.

Solidifying the first adhesive can include mechanically bonding thefirst post and the base to the first conductive layer Likewise,solidifying the second adhesive can include mechanically bonding thesecond post and the base to the second conductive layer.

Mounting the semiconductor device on the first post can include mountingthe semiconductor device on the first cap and thus the first post.Mounting the semiconductor device can also include positioning thesemiconductor device within peripheries of the posts and caps andoutside the periphery of the conductive trace, or alternatively,positioning the semiconductor device to extend within the peripheries ofthe posts, the caps and the pad.

Mounting the semiconductor device can include providing a first solderjoint between an LED package that includes an LED chip and the pad and asecond solder joint between the LED package and the first cap,electrically connecting the semiconductor device can include providingthe first solder joint between the LED package and the pad, andthermally connecting the semiconductor device can include providing thesecond solder joint between the LED package and the first cap.

Mounting the semiconductor device can include providing a die attachbetween a semiconductor chip such as an LED chip and the first cap,electrically connecting the semiconductor device can include providing awire bond between the chip and the pad, and thermally connecting thesemiconductor device can include providing the die attach between thechip and the first cap.

The semiconductor device can be encapsulated by providing an encapsulanton the thermal board that covers the semiconductor device in the firstvertical direction.

The first adhesive can contact the base, the first post and the firstcap, be spaced from the terminal, the second post and the secondadhesive, cover and surround the first post in the lateral directionsand extend to peripheral edges of the assembly after the assembly ismanufactured and detached from other assemblies in a batch.

The second adhesive can contact the base, the second post and the secondcap, be spaced from the pad, the first post and the first adhesive,cover and surround the second post in the lateral directions and extendto peripheral edges of the assembly after the assembly is manufacturedand detached from other assemblies in a batch.

The base can cover the semiconductor device, the first post, the firstcap and the pad in the second vertical direction, cover the second post,the second cap and the terminal in the first vertical direction, supportthe adhesives and extend to peripheral edges of the assembly after theassembly is manufactured and detached from other assemblies in a batch.

The present invention has numerous advantages. The heat spreader canprovide excellent heat spreading and heat dissipation without heat flowthrough the adhesives. As a result, the adhesives can be a low costdielectric with low thermal conductivity and not prone to delamination.The posts and the base can be integral with one another, therebyenhancing reliability. The first post can provide thermal expansionmatching with a semiconductor device mounted thereon, thereby increasingreliability. The first cap can be customized for the semiconductordevice, thereby enhancing the thermal connection. The first adhesive canbe sandwiched between the base and the pad and the second adhesive canbe sandwiched between the base and the terminal, thereby providing arobust mechanical bond between the heat spreader and the conductivetrace. The conductive trace can provide signal routing with simplecircuitry patterns or flexible multi-layer signal routing with complexcircuitry patterns. The conductive trace can also provide verticalsignal routing between the pad and the terminal. The electricalinterconnect can be a plated through-hole formed after the adhesives aresolidified and remain a hollow tube or be split at a peripheral edge ofthe assembly. As a result, a solder joint subsequently reflowed on theterminal can wet and flow into the plated through-hole without creatinga buried void in the solder joint beneath the plated through-hole thatmight otherwise occur if the plated through-hole is filled with theadhesives or another non-wettable insulator, thereby increasingreliability. The base can provide mechanical support for the conductivelayers and the adhesives, thereby preventing warping. The assembly canbe manufactured using low temperature processes which reduces stress andimproves reliability. The assembly can also be manufactured usingwell-controlled processes which can be easily implemented by circuitboard, lead frame and tape manufacturers.

These and other features and advantages of the present invention will befurther described and more readily apparent from a review of thedetailed description of the preferred embodiments which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of the preferred embodiments of thepresent invention can best be understood when read in conjunction withthe following drawings, in which:

FIGS. 1A-1D are cross-sectional views showing a method of making firstand second posts and a base in accordance with an embodiment of thepresent invention;

FIGS. 1E and 1F are top and bottom views, respectively, corresponding toFIG. 1D;

FIGS. 2A and 2B are cross-sectional views showing a method of making afirst conductive layer in accordance with an embodiment of the presentinvention;

FIGS. 2C and 2D are top and bottom views, respectively, corresponding toFIG. 2B;

FIGS. 3A and 3B are cross-sectional views showing a method of making asecond conductive layer in accordance with an embodiment of the presentinvention;

FIGS. 3C and 3D are top and bottom views, respectively, corresponding toFIG. 3B;

FIGS. 4A and 4B are cross-sectional views showing a method of making afirst adhesive in accordance with an embodiment of the presentinvention;

FIGS. 4C and 4D are top and bottom views, respectively, corresponding toFIG. 4B;

FIGS. 5A and 5B are cross-sectional views showing a method of making asecond adhesive in accordance with an embodiment of the presentinvention;

FIGS. 5C and 5D are top and bottom views, respectively, corresponding toFIG. 5B;

FIGS. 6A-6Q are cross-sectional views showing a method of making athermal board in accordance with an embodiment of the present invention;

FIGS. 6R and 6S are top and bottom views, respectively, corresponding toFIG. 6Q;

FIGS. 7A, 7B and 7C are cross-sectional, top and bottom views,respectively, of a thermal board with a plated through-hole at aperipheral edge in accordance with an embodiment of the presentinvention;

FIGS. 8A, 8B and 8C are cross-sectional, top and bottom views,respectively, of a thermal board with a pad and a first cap with thesame thickness and a terminal and a second cap with the same thicknessin accordance with an embodiment of the present invention;

FIGS. 9A, 9B and 9C are cross-sectional, top and bottom views,respectively, of a thermal board with dielectric layers in accordancewith an embodiment of the present invention;

FIGS. 10A, 10B and 10C are cross-sectional, top and bottom views,respectively, of a thermal board with a rim in accordance with anembodiment of the present invention;

FIGS. 11A, 11B and 11C are cross-sectional, top and bottom views,respectively, of a thermal board with solder masks in accordance with anembodiment of the present invention;

FIGS. 12A, 12B and 12C are cross-sectional, top and bottom views,respectively, of a semiconductor chip assembly that includes a thermalboard, a semiconductor device and an encapsulant in accordance with anembodiment of the present invention;

FIGS. 13A, 13B and 13C are cross-sectional, top and bottom views,respectively, of a semiconductor chip assembly that includes a thermalboard with a rim, a semiconductor device and a lid in accordance with anembodiment of the present invention; and

FIGS. 14A, 14B and 14C are cross-sectional, top and bottom views,respectively, of a semiconductor chip assembly that includes a thermalboard with solder masks and a semiconductor device with backsidecontacts in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A-1D are cross-sectional views showing a method of making firstand second posts and a base in accordance with an embodiment of thepresent invention, and FIGS. 1E and 1F are top and bottom views,respectively, corresponding to FIG. 1D.

FIG. 1A. is a cross-sectional view of metal plate 10 which includesopposing major surfaces 12 and 14. Metal plate 10 is illustrated as acopper plate with a thickness of 500 microns. Copper has high thermalconductivity, good bondability and low cost. Metal plate 10 can bevarious metals such as copper, aluminum, alloy 42, iron, nickel, silver,gold, combinations thereof, and alloys thereof.

FIG. 1B is a cross-sectional view of etch masks 16 and 18 formed onmetal plate 10. Etch masks 16 and 18 are illustrated as photoresistlayers which are deposited on metal plate 10 using dry film laminationin which hot rolls simultaneously press photoresist layers 16 and 18onto surfaces 12 and 14, respectively. Wet spin coating and curtaincoating are also suitable deposition techniques. A first reticle (notshown) is positioned proximate to photoresist layer 16 and a secondreticle (not shown) is positioned proximate to photoresist layer 18.Thereafter, photoresist layers 16 and 18 are patterned by selectivelyapplying light through the first and second reticles, respectively, sothat the photoresist portions exposed to the light are renderedinsoluble, applying a developer solution to remove the photoresistportions that are unexposed to the light and remain soluble and thenhard baking, as is conventional. As a result, photoresist layer 16 has apattern that selectively exposes surface 12 and photoresist layer 18 hasa pattern that selectively exposes surface 14.

FIG. 1C is a cross-sectional view of recesses 20 and 22 formed into butnot through metal plate 10 by etching metal plate 10 in the patternsdefined by etch masks 16 and 18, respectively. The etching isillustrated as a frontside and backside wet chemical etch. For instance,a top spray nozzle (not shown) and a bottom spray nozzle (not shown) canspray the wet chemical etch on the top and bottom of the structure, orthe structure can be dipped in the wet chemical etch.

The wet chemical etch is highly selective of copper and etches 150microns into metal plate 10 from the frontside and backside. As aresult, recess 20 extends from surface 12 into but not through metalplate 10 and has a depth of 150 microns and recess 22 extends fromsurface 14 into but not through metal plate 10 and has a depth of 150microns. The wet chemical etch also laterally undercuts metal plate 10beneath etch mask 16 and above etch mask 18. A suitable wet chemicaletch can be provided by a solution containing alkaline ammonia or adilute mixture of nitric and hydrochloric acid. Likewise, the wetchemical etch can be acidic or alkaline. The optimal etch time forforming recesses 20 and 22 without excessively exposing metal plate 10to the wet chemical etch can be established through trial and error.

FIGS. 1D, 1E and 1F are cross-sectional, top and bottom views,respectively, of metal plate 10 after etch masks 16 and 18 are removed.The photoresist layers are stripped using a solvent, such as a strongalkaline solution containing potassium hydroxide with a pH of 14, thatis highly selective of photoresist with respect to copper.

Metal plate 10 as etched includes posts 24 and 26 and base 28.

Post 24 is an unetched portion of metal plate 10 defined by etch mask16. Post 24 is adjacent to and integral with and protrudes above base 28and is laterally surrounded by recess 20. Post 24 has a height of 150microns (recess 20 depth), a diameter at its top surface (circularportion of surface 12) of 1000 microns and a diameter at its bottom(circular portion adjacent to base 28) of 1200 microns. Thus, post 24has a cut-off conical shape (resembling a frustum) with taperedsidewalls in which its diameter decreases as it extends upwardly frombase 28 to its flat circular top surface. The tapered sidewalls arisefrom the lateral undercutting by the wet chemical etch beneath etch mask16. The top surface is concentrically disposed within a periphery of thebottom (shown in phantom in FIG. 1E).

Post 26 is an unetched portion of metal plate 10 defined by etch mask18. Post 26 is adjacent to and integral with and protrudes below base 28and is laterally surrounded by recess 22. Post 26 has a height of 150microns (recess 22 depth), a diameter at its bottom surface (circularportion of surface 14) of 1000 microns and a diameter at its top(circular portion adjacent to base 28) of 1200 microns. Thus, post 26has a cut-off conical shape (resembling a frustum) with taperedsidewalls in which its diameter decreases as it extends downwardly frombase 28 to its flat circular bottom surface. The tapered sidewalls arisefrom the lateral undercutting by the wet chemical etch above etch mask18. The bottom surface is concentrically disposed within a periphery ofthe top (shown in phantom in FIG. 1F).

Posts 24 and 26 are mirror images of one another, are axially alignedwith one another and are vertically offset from one another by base 28.

Base 28 is an unetched portion of metal plate 10 that is below post 24,above post 26, covers post 24 in the downward direction, covers post 26in the upward direction, is sandwiched between posts 24 and 26, extendslaterally from posts 24 and 26 in a lateral plane (with lateraldirections such as left and right) and has a thickness of 200 microns(500-150-150).

Posts 24 and 26 and base 28 can be treated to improve bondability toepoxy and solder. For instance, posts 24 and 26 and base 28 can bechemically oxidized or microetched to provide rougher surfaces.

Posts 24 and 26 and base 28 are illustrated as a subtractively formedsingle-piece metal (copper). Posts 24 and 26 and base 28 can also be astamped single-piece metal formed by stamping metal plate 10 with acontact piece with a recess or hole that defines post 24 and a recess orhole that defines post 26. Posts 24 and 26 can also be formed additivelyby depositing posts 24 and 26 on base 28 using electroplating, chemicalvapor deposition (CVD), physical vapor deposition (PVD) and so on, forinstance by electroplating a solder post 24 and a solder post 26 on acopper base 28, in which case post 24 and base 28 have a metallurgicalinterface and are adjacent to but not integral with one another and post26 and base 28 have a metallurgical interface and are adjacent to butnot integral with one another. Posts 24 and 26 can also be formedsemi-additively, for instance by depositing upper portions of post 24 onetch-defined lower portions of post 24 and lower portions of post 26 onetch-defined upper portions of post 26. Posts 24 and 26 can also beformed semi-additively by depositing conformal upper portions of post 24on etch-defined lower portions of post 24 and depositing conformal lowerportions of post 26 on etch-defined upper portions of post 26. Posts 24and 26 can also be sintered to base 28.

FIGS. 2A and 2B are cross-sectional views showing a method of making afirst conductive layer in accordance with an embodiment of the presentinvention, and FIGS. 2C and 2D are top and bottom views, respectively,corresponding to FIG. 2B.

FIG. 2A is a cross-sectional view of conductive layer 30. For instance,conductive layer 30 is an unpatterned copper sheet with a thickness of80 microns.

FIGS. 2B, 2C and 2D are cross-sectional, top and bottom views,respectively, of conductive layer 30 with aperture 30A. Aperture 30A isa window that extends through conductive layer 30 and has a diameter of1250 microns. Aperture 30A is formed by mechanical drilling throughconductive layer 30 although other techniques such as wet chemicaletching, punching and stamping can be used.

FIGS. 3A and 3B are cross-sectional views showing a method of making asecond conductive layer in accordance with an embodiment of the presentinvention, and FIGS. 3C and 3D are top and bottom views, respectively,corresponding to FIG. 3B.

FIG. 3A is a cross-sectional view of conductive layer 32. For instance,conductive layer 32 is an unpatterned copper sheet with a thickness of80 microns that is identical to conductive layer 30.

FIGS. 3B, 3C and 3D are cross-sectional, top and bottom views,respectively, of conductive layer 32 with aperture 32A. Aperture 32A isa window that extends through conductive layer 32 and has a diameter of1250 microns. Aperture 32A is formed by mechanical drilling throughconductive layer 32 although other techniques such as wet chemicaletching, punching and stamping can be used.

FIGS. 4A and 4B are cross-sectional views showing a method of making afirst adhesive in accordance with an embodiment of the presentinvention, and FIGS. 4C and 4D are top and bottom views, respectively,corresponding to FIG. 4B.

FIG. 4A is a cross-sectional view of adhesive 34. Adhesive 34 isillustrated as a prepreg with B-stage uncured epoxy provided as anon-solidified unpatterned sheet with a thickness of 100 microns.

Adhesive 34 can be various dielectric films or prepregs formed fromnumerous organic or inorganic electrical insulators. For instance,adhesive 34 can initially be a prepreg in which thermosetting epoxy inresin form impregnates a reinforcement and is partially cured to anintermediate stage. The epoxy can be FR-4 although other epoxies such aspolyfunctional and bismaleimide triazine (BT) are suitable. For specificapplications, cyanate esters, polyimide and PTFE are also suitable. Thereinforcement can be E-glass although other reinforcements such asS-glass, D-glass, quartz, kevlar aramid and paper are suitable. Thereinforcement can also be woven, non-woven or random microfiber. Afiller such as silica (powdered fused quartz) can be added to theprepreg to improve thermal conductivity, thermal shock resistance andthermal expansion matching. Commercially available prepregs such asSPEEDBOARD C prepreg by W.L. Gore & Associates of Eau Claire, Wis. aresuitable.

FIGS. 4B, 4C and 4D are cross-sectional, top and bottom views,respectively, of adhesive 34 with opening 34A. Opening 34A is a windowthat extends through adhesive 34 and has a diameter of 1250 microns.Opening 34A is formed by mechanical drilling through the prepregalthough other techniques such as punching and stamping can be used.

FIGS. 5A and 5B are cross-sectional views showing a method of making asecond adhesive in accordance with an embodiment of the presentinvention, and FIGS. 5C and 5D are top and bottom views, respectively,corresponding to FIG. 5B.

FIG. 5A is a cross-sectional view of adhesive 36. Adhesive 36 isillustrated as a prepreg with B-stage uncured epoxy provided as anon-solidified unpatterned sheet with a thickness of 100 microns that isidentical to adhesive 34.

FIGS. 5B, 5C and 5D are cross-sectional, top and bottom views,respectively, of adhesive 36 with opening 36A. Opening 36A is a windowthat extends through adhesive 36 and has a diameter of 1250 microns.Opening 36A is formed by mechanical drilling through the prepregalthough other techniques such as punching and stamping can be used.

Conductive layers 30 and 32 are identical copper sheets and adhesives 34and 36 are identical prepregs. Furthermore, apertures 30A and 32A andopenings 34A and 36A have the same diameter and can be formed in thesame manner with the same drill bit at the same drilling station.

FIGS. 6A-6Q are cross-sectional views showing a method of making athermal board that includes posts 24 and 26, base 28, conductive layers30 and 32 and adhesives 34 and 36 in accordance with an embodiment ofthe present invention, and FIGS. 6R and 6S are top and bottom views,respectively, corresponding to FIG. 6Q.

In FIGS. 6A and 6B the structure is inverted so that post 26 protrudesabove base 28 and post 24 protrudes below base 28. Thereafter, in FIGS.6C-6Q the structure is upright as in FIGS. 1A-1D so that post 24protrudes above base 28 and post 26 protrudes below base 28. As aresult, gravity assists with mounting conductive layer 32 and adhesive36 on base 28 in FIGS. 6A and 6B, and thereafter gravity assists withmounting conductive layer 30 and adhesive 34 on base 28 in FIGS. 6D and6E. However, the relative orientation of the structure does not change.Post 24 extends from base 28 in the first vertical direction and iscovered by base 28 in the second vertical direction and post 26 extendsfrom base 28 in the second vertical direction and is covered by base 28in the first vertical direction and regardless of whether the structureis inverted, rotated or slanted. Likewise, adhesive 34 extends beyondbase 28 in the first vertical direction and adhesive 36 extends beyondbase 28 in the second vertical direction regardless of whether thestructure is inverted, rotated or slanted. Hence, the first and secondvertical directions are oriented relative to the structure and remainopposite to one another and orthogonal to the lateral directions.

FIG. 6A is a cross-sectional view of the structure with adhesive 36mounted on base 28. Adhesive 36 is mounted by lowering it onto base 28as post 26 is inserted upwards and into and through opening 36A.Adhesive 36 eventually contacts and rests on base 28. Post 26 isinserted into and extends through and above opening 36A withoutcontacting adhesive 36 and is aligned with and centrally located withinopening 36A.

FIG. 6B is a cross-sectional view of the structure with conductive layer32 mounted on adhesive 36. Conductive layer 32 is mounted by lowering itonto adhesive 36 as post 26 is inserted upward and into but not throughaperture 32A. Conductive layer 32 eventually contacts and rests onadhesive 36. Post 26 is inserted into and extends into but not throughaperture 32A without contacting conductive layer 32 and is aligned withand centrally located within aperture 32A. In addition, aperture 32A andopening 36A are precisely aligned with one another and have the samediameter.

FIG. 6C is a cross-sectional view of the structure after it is inverted.As a result, adhesive 36 is mounted on conductive layer 32 and base 28is mounted on adhesive 36.

FIG. 6D is a cross-sectional view of the structure with adhesive 34mounted on base 28. Adhesive 34 is mounted by lowering it onto base 28as post 24 is inserted upwards and into and through opening 34A.Adhesive 34 eventually contacts and rests on base 28. Post 24 isinserted into and extends through and above opening 34A withoutcontacting adhesive 34 and is aligned with and centrally located withinopening 34A.

FIG. 6E is a cross-sectional view of the structure with conductive layer30 mounted on adhesive 34. Conductive layer 30 is mounted by lowering itonto adhesive 34 as post 24 is inserted upward and into but not throughaperture 30A. Conductive layer 30 eventually contacts and rests onadhesive 34. Post 24 is inserted into and extends into but not throughaperture 30A without contacting conductive layer 30 and is aligned withand centrally located within aperture 30A. In addition, aperture 30A andopening 34A are precisely aligned with one another and have the samediameter.

At this stage, conductive layer 30 is mounted on and contacts andextends above adhesive 34, adhesive 34 is mounted on and contacts andextends above base 28, base 28 is mounted on and contacts and extendsabove adhesive 36 and adhesive 36 is mounted on and contacts and extendsabove conductive layer 32. Thus, base 28 contacts and is sandwichedbetween adhesives 34 and 36 and is spaced from conductive layers 30 and32, adhesive 34 contacts and is sandwiched between base 28 andconductive layer 30 and is spaced from conductive layer 32 and adhesive36 and adhesive 36 contacts and is sandwiched between base 28 andconductive layer 32 and is spaced from conductive layer 30 and adhesive34.

Post 24 extends through opening 34A into aperture 30A, is aligned withaperture 30A and opening 34A, is 30 microns below the top surface ofconductive layer 30 and is exposed through aperture 30A in the upwarddirection. Post 24 remains adjacent to and integral with base 28 andspaced from conductive layer 30 and adhesive 34.

Post 26 extends through opening 36A into aperture 32A, is aligned withaperture 32A and opening 36A, is 30 microns above the bottom surface ofconductive layer 32 and is exposed through aperture 32A in the downwarddirection. Post 26 remains adjacent to and integral with base 28 andspaced from conductive layer 32 and adhesive 36.

Adhesive 34 remains a non-solidified prepreg with B-stage uncured epoxy,adhesive 36 remains a non-solidified prepreg with B-stage uncured epoxyand adhesives 34 and 36 remain spaced from one another.

FIG. 6F is a cross-sectional view of the structure with adhesives 34 and36 flowed into contact with posts 24 and 26, respectively.

Gap 40 is located in aperture 30A between post 24 and conductive layer30 and gap 42 is located in aperture 32A between post 26 and conductivelayer 32. Gap 40 laterally surrounds post 24 and is laterally surroundedby conductive layer 30 and gap 42 laterally surrounds post 26 and islaterally surrounded by conductive layer 32.

Adhesive 34 is flowed into gap 40 and adhesive 36 is flowed into gap 42by applying heat and pressure. In this illustration, adhesive 34 isforced into gap 40 and adhesive 36 is forced into gap 42 by applyingdownward pressure to conductive layer 30 and/or upward pressure toconductive layer 32, thereby moving base 28 and conductive layer 30towards one another, moving base 28 and conductive layer 32 towards oneanother and applying pressure to adhesives 34 and 36 whilesimultaneously applying heat to adhesives 34 and 36. Adhesives 34 and 36become compliant enough under the heat and pressure to conform tovirtually any shape. As a result, adhesive 34 sandwiched between base 28and conductive layer 30 is compressed, forced out of its original shapeand flows into and upward in gap 40. Likewise, adhesive 36 sandwichedbetween base 28 and conductive layer 32 is compressed, forced out of itsoriginal shape and flows into and downward in gap 42. Base 28 andconductive layer 30 continue to move towards one another and adhesive 34eventually fills gap 40. Likewise, base 28 and conductive layer 32continue to move towards one another and adhesive 36 eventually fillsgap 42. Moreover, adhesive 34 remains sandwiched between and continuesto fill the reduced space between base 28 and conductive layer 30 andadhesive 36 remains sandwiched between and continues to fill the reducedspace between base 28 and conductive layer 32.

For instance, conductive layers 30 and 32 can be disposed between topand bottom platens (not shown) of a press. In addition, a top cull plateand top buffer paper (not shown) can be sandwiched between conductivelayer 30 and the top platen, and a bottom cull plate and bottom bufferpaper (not shown) can be sandwiched between conductive layer 32 and thebottom platen. The stack includes the top platen, top cull plate, topbuffer paper, conductive layer 30, adhesive 34, base 28, adhesive 36,conductive layer 32, bottom buffer paper, bottom cull plate and bottomplaten in descending order. Furthermore, the stack may be positioned onthe bottom platen by tooling pins (not shown) that extend upward fromthe bottom platen through registration holes (not shown) in metal plate10.

The platens are heated and move towards one another, thereby applyingheat and pressure to adhesives 34 and 36. The cull plates disperse theheat from the platens so that it is more uniformly applied to conductivelayers 30 and 32 and thus adhesives 34 and 36, and the buffer papersdisperse the pressure from the platens so that it is more uniformlyapplied to conductive layers 30 and 32 and thus adhesives 34 and 36.Initially, conductive layer 30 contacts and presses down on adhesive 34and conductive layer 32 contacts and presses up on adhesive 36.

As the platen motion and heat continue, adhesive 34 between base 28 andconductive layer 30 is compressed, melted and flows into and upward ingap 40 and adhesive 36 between base 28 and conductive layer 32 iscompressed, melted and flows into and downward in gap 42. For instance,in adhesive 34 the uncured epoxy is melted by the heat and the moltenuncured epoxy is squeezed by the pressure into gap 40, however thereinforcement and the filler remain between base 28 and conductive layer30. Likewise, in adhesive 36 the uncured epoxy is melted by the heat andthe molten uncured epoxy is squeezed by the pressure into gap 42,however the reinforcement and the filler remain between base 28 andconductive layer 32.

Adhesive 34 ascends more rapidly than post 24 in aperture 30A, fills andextends slightly above gap 40 and overflows onto the top surfaces ofpost 24 and conductive layer 30 adjacent to gap 40 before the platenmotion stops. This may occur due to the prepreg being slightly thickerthan necessary. As a result, adhesive 34 creates a thin coating on thetop surfaces of post 24 and conductive layer 30.

Adhesive 36 descends more rapidly than post 26 in aperture 32A, fillsand extends slightly below gap 42 and overflows onto the bottom surfacesof post 26 and conductive layer 32 adjacent to gap 42 before the platenmotion stops. This may occur due to the prepreg being slightly thickerthan necessary. As a result, adhesive 36 creates a thin coating on thebottom surfaces of post 26 and conductive layer 32.

The platen motion is eventually blocked by posts 24 and 26 and theplatens become stationary but continue to apply heat to adhesives 34 and36.

The upward flow of adhesive 34 in gap 40 is shown by the thick upwardarrows, the downward flow of adhesive 36 in gap 42 is shown by the thickdownward arrows, the upward motion of conductive layer 32 relative topost 26 and base 28 is shown by the thin upward arrows, and the downwardmotion of conductive layer 30 relative to post 24 and base 28 is shownby the thin downward arrows.

FIG. 6G is a cross-sectional view of the structure with adhesives 34 and36 solidified.

For instance, the platens continue to clamp posts 24 and 26 and applyheat after the platen motion stops, thereby converting the B-stagemolten uncured epoxy into C-stage cured or hardened epoxy. Thus, theepoxy is cured in a manner similar to conventional multi-layerlamination. After the epoxy is cured, the platens move away from oneanother and the structure is released from the press.

Adhesive 34 as solidified provides a secure robust mechanical bondbetween post 24 and conductive layer 30 and between base 28 andconductive layer 30. Adhesive 34 can withstand normal operating pressurewithout distortion or damage and is only temporarily distorted underunusually high pressure. Furthermore, adhesive 34 can absorb thermalexpansion mismatch between post 24 and conductive layer 30 and betweenbase 28 and conductive layer 30.

Adhesive 36 as solidified provides a secure robust mechanical bondbetween post 26 and conductive layer 32 and between base 28 andconductive layer 32. Adhesive 36 can withstand normal operating pressurewithout distortion or damage and is only temporarily distorted underunusually high pressure. Furthermore, adhesive 36 can absorb thermalexpansion mismatch between post 26 and conductive layer 32 and betweenbase 28 and conductive layer 32.

Post 24 and conductive layer 30 are essentially coplanar with oneanother and conductive layer 30 and adhesive 34 extend to a top surfacethat faces in the upward direction. For instance, adhesive 34 betweenbase 28 and conductive layer 30 has a thickness of 70 microns which is30 microns less than its initial thickness of 100 microns, post 24ascends 30 microns in aperture 30A and conductive layer 30 descends 30microns relative to post 24. The 150 micron height of post 24 isessentially the same as the combined height of conductive layer 30 (80microns) and the underlying adhesive 34 (70 microns). Furthermore, post24 continues to be centrally located in aperture 30A and opening 34A andspaced from conductive layer 30 and adhesive 36 fills the space betweenpost 24 and conductive layer 30, fills the space between base 28 andconductive layer 30 and fills gap 40. For instance, gap 40 (as well asadhesive 34 between post 24 and conductive layer 30) has a width of 125microns ((1250−1000)/2) at the top surface of post 24.

Post 26 and conductive layer 32 are essentially coplanar with oneanother and conductive layer 32 and adhesive 36 extend to a bottomsurface that faces in the downward direction. For instance, adhesive 36between base 28 and conductive layer 32 has a thickness of 70 micronswhich is 30 microns less than its initial thickness of 100 microns, post26 descends 30 microns in aperture 32A and conductive layer 32 ascends30 microns relative to post 26. The 150 micron height of post 26 isessentially the same as the combined height of conductive layer 32 (80microns) and the overlying adhesive 36 (70 microns). Furthermore, post26 continues to be centrally located in aperture 32A and opening 36A andspaced from conductive layer 32 and adhesive 34 fills the space betweenpost 26 and conductive layer 32, fills the space between base 28 andconductive layer 32 and fills gap 42. For instance, gap 42 (as well asadhesive 36 between post 26 and conductive layer 32) has a width of 125microns ((1250−1000)/2) at the bottom surface of post 26.

Adhesive 34 extends across conductive layer 30 in gap 40. That is,adhesive 34 in gap 40 extends in the upward and downward directionsacross the thickness of conductive layer 30 at the outer sidewall of gap40. Adhesive 34 also includes a thin top portion above gap 40 thatcontacts the top surfaces of post 24 and conductive layer 30 and extendsabove post 24 by 10 microns.

Adhesive 36 extends across conductive layer 32 in gap 42. That is,adhesive 36 in gap 42 extends in the upward and downward directionsacross the thickness of conductive layer 32 at the outer sidewall of gap42. Adhesive 36 also includes a thin bottom portion below gap 42 thatcontacts the bottom surfaces of post 26 and conductive layer 32 andextends below post 26 by 10 microns.

FIG. 6H is a cross-sectional view of the structure with outer hole 44.Outer hole 44 is a through-hole that extends through and is adjacent tobase 28, conductive layers 30 and 32 and adhesives 34 and 36 and has adiameter of 500 microns. Outer hole 44 is formed by mechanical drillingthrough base 28, conductive layers 30 and 32 and adhesives 34 and 36although other techniques such as laser drilling, plasma etching and wetchemical etching can be used.

FIG. 6I is a cross-sectional view of the structure with insulativefiller 46 in outer hole 44. Insulative filler 46 is an electricallyinsulative epoxy that is located within and fills outer hole 44,contacts base 28, conductive layer 30 and 32 and adhesives 34 and 36 inouter hole 44 and is spaced from posts 24 and 26.

Insulative filler 46 is initially an epoxy paste that is selectivelyscreen printed into outer hole 44. Thereafter, the epoxy paste is heatedand hardened at a relatively low temperature such as 190° C.

Insulative filler 46 can be various dielectric films formed fromnumerous organic and inorganic electrical insulators. For instance,insulative filler 46 can be polyimide or FR-4 epoxy although otherepoxies such as polyfunctional and bismaleimide triazine (BT) aresuitable.

FIG. 6J is a cross-sectional view of the structure after upper portionsof post 24, conductive layer 30, adhesive 34 and insulative filler 46are removed and lower portions of post 26, conductive layer 32, adhesive36 and insulative filler 46 are removed.

Post 24, conductive layer 30, adhesive 34 and insulative filler 46 havetheir upper portions removed by grinding. For instance, a rotatingdiamond sand wheel and distilled water are applied to the top of thestructure. Initially, the diamond sand wheel grinds only adhesive 34. Asthe grinding continues, adhesive 34 becomes thinner as its grindedsurface migrates downwardly. Eventually the diamond sand wheel contactspost 24, conductive layer 30 and insulative filler 46 (not necessarilyat the same time), and as a result, begins to grind post 24, conductivelayer 30 and insulative filler 46 as well. As the grinding continues,post 24, conductive layer 30, adhesive 34 and insulative filler 46become thinner as their grinded surfaces migrate downwardly. Thegrinding continues until the desired thickness has been removed.Thereafter, the structure is rinsed in distilled water to removecontaminants.

The grinding removes a 30 micron thick upper portion of adhesive 34, a20 micron thick upper portion of post 24, a 20 micron thick upperportion of conductive layer 30 and a 20 micron thick upper portion ofinsulative filler 46. The decreased thickness does not appreciablyaffect post 24, conductive layer 30, adhesive 34 or insulative filler46.

Post 26, conductive layer 32, adhesive 36 and insulative filler 46 havetheir lower portions removed by grinding. For instance, a rotatingdiamond sand wheel and distilled water are applied to the bottom of thestructure. Initially, the diamond sand wheel grinds only adhesive 36. Asthe grinding continues, adhesive 36 becomes thinner as its grindedsurface migrates upwardly. Eventually the diamond sand wheel contactspost 26, conductive layer 32 and insulative filler 46 (not necessarilyat the same time), and as a result, begins to grind post 26, conductivelayer 32 and insulative filler 46 as well. As the grinding continues,post 26, conductive layer 32, adhesive 36 and insulative filler 46become thinner as their grinded surfaces migrate upwardly. The grindingcontinues until the desired thickness has been removed. Thereafter, thestructure is rinsed in distilled water to remove contaminants.

The grinding removes a 30 micron thick lower portion of adhesive 36, a20 micron thick lower portion of post 26, a 20 micron thick lowerportion of conductive layer 32 and a 20 micron thick lower portion ofinsulative filler 46. The decreased thickness does not appreciablyaffect post 26, conductive layer 32, adhesive 36 or insulative filler46.

At this stage, post 24, conductive layer 30, adhesive 34 and insulativefiller 46 are coplanar with one another at a smoothed lapped lateral topsurface that is above base 28 and faces in the upward direction.Likewise, post 26, conductive layer 32, adhesive 36 and insulativefiller 46 are coplanar with one another at a smoothed lapped lateralbottom surface that is below base 28 and faces in the downwarddirection.

FIG. 6K is a cross-sectional view of the structure with inner hole 50 inouter hole 44. Inner hole 50 is a through-hole that is located withinand extends through and is coaxial with outer hole 44. Inner hole 50 islocated within and extends through and is adjacent to insulative filler46, extends through and is spaced from base 28, conductive layers 30 and32 and adhesives 34 and 36 and has a diameter of 300 microns. Thus,inner hole 50 has its sidewall at insulative filler 46 and is spacedfrom base 28, conductive layers 30 and 32 and adhesives 34 and 36 by 100microns ((500−300)/2). Inner hole 50 is formed by mechanical drillingthrough insulative filler 46 although other techniques such as laserdrilling and plasma etching can be used.

FIG. 6L is a cross-sectional view of the structure with plated metal 52deposited on posts 24 and 26, conductive layers 30 and 32, adhesives 34and 36 and insulative filler 46. Plated metal 52 forms plated layer 54,plated layer 56 and plated through-hole 58.

Plated layer 54 is deposited on and contacts post 24, conductive layer30, adhesive 34 and insulative filler 46 at the lateral top surface andcovers them in the upward direction. Plated layer 54 is an unpatternedcopper layer with a thickness of 20 microns.

Plated layer 56 is deposited on and contacts post 26, conductive layer32, adhesive 36 and insulative filler 46 at the lateral bottom surfaceand covers them in the downward direction. Plated layer 56 is anunpatterned copper layer with a thickness of 20 microns.

Plated through-hole 58 is deposited on and contacts insulative filler 46in inner hole 50 and covers the sidewall in the lateral directions.Plated through-hole 58 is a copper tube with a thickness of 20 micronsand is adjacent to and integral with and electrically connects platedlayers 54 and 56. Furthermore, plated through-hole 58 is spaced frombase 28 and adhesives 34 and 36 by 100 microns ((500−300)/2).

For instance, the structure is dipped in an activator solution to renderadhesives 34 and 36 and insulative filler 46 catalytic to electrolesscopper, then a first copper layer is electroles sly plated on posts 24and 26, conductive layers 30 and 32, adhesives 34 and 36 and insulativefiller 46, and then a second copper layer is electroplated on the firstcopper layer. The first copper layer has a thickness of 2 microns, thesecond copper layer has a thickness of 18 microns, and plated metal 52(and plated layers 54 and 56 and plated through-hole 58) has a thicknessof 20 microns. As a result, conductive layer 30 essentially grows andhas a thickness of 80 microns (60+20) and conductive layer 32essentially grows and has a thickness of 80 microns (60+20).

Plated layer 54 serves as a cover layer for post 24, adhesive 34 andinsulative filler 46 and a build-up layer for conductive layer 30,plated layer 56 serves as a cover layer for post 26, adhesive 36 andinsulative filler 46 and a build-up layer for conductive layer 32 andplated through-hole 58 serves as an electrical interconnect betweenplated layers 54 and 56 and thus conductive layers 30 and 32.

Post 24, conductive layer 30, plated layer 54 and plated through-hole 58are shown as a single layer for convenience of illustration. Likewise,post 26, conductive layer 32, plated layer 56 and plated through-hole 58are shown as a single layer for convenience of illustration. Theboundary (shown in phantom) between post 24 and plated layer 54, betweenconductive layer 30 and plated layer 54, between post 26 and platedlayer 56 and between conductive layer 32 and plated layer 56 may bedifficult or impossible to detect since copper is plated on copper.However, the boundary between adhesive 34 and plated layer 54, betweeninsulative filler 46 and plated layer 54, between adhesive 36 and platedlayer 56, between insulative filler 46 and plated layer 56 and betweeninsulative filler 46 and plated through-hole 58 is clear.

FIG. 6M is a cross-sectional view of the structure with etch masks 60and 62 formed on plated layers 54 and 56, respectively. Etch masks 60and 62 are illustrated as photoresist layers similar to photoresistlayers 16 and 18, respectively. Photoresist layer 60 has a pattern thatselectively exposes plated layer 54, and photoresist layer 62 has apattern that selectively exposes plated layer 56.

FIG. 6N is a cross-sectional view of the structure with selectedportions of conductive layer 30 and plated layer 54 removed by etchingconductive layer 30 and plated layer 54 in the pattern defined by etchmask 60, and selected portions of conductive layer 32 and plated layer56 removed by etching conductive layer 32 and plated layer 56 in thepattern defined by etch mask 62. The etching is a frontside and backsidewet chemical etch similar to the etch applied to metal plate 10. Forinstance, a top spray nozzle (not shown) and a bottom spray nozzle (notshown) can spray the wet chemical etch on the top and bottom of thestructure, or the structure can be dipped in the wet chemical etch. Thewet chemical etch etches through conductive layer 30 and plated layer 54to expose adhesive 34 in the upward direction without exposing base 28or adhesive 36 in the upward direction and converts conductive layer 30and plated layer 54 from unpatterned into patterned layers. The wetchemical etch also etches through conductive layer 32 and plated layer56 to expose adhesive 36 in the downward direction without exposing base28 or adhesive 34 in the downward direction and converts conductivelayer 32 and plated layer 56 from unpatterned into patterned layers.

FIG. 6O is a cross-sectional view of the structure after etch masks 60and 62 are removed. Photoresist layers 60 and 62 can be stripped in thesame manner as photoresist layers 16 and 18.

Conductive layer 30 and plated layer 54 as etched include pad 64,routing line 66 and cap 68. Pad 64, routing line 66 and cap 68 areunetched portions of conductive layer 30 and plated layer 54 defined byetch mask 60. Thus, conductive layer 30 and plated layer 54 are apatterned layer that includes pad 64, routing line 66 and cap 68.

Pad 64 is an unetched portion of conductive layer 30 and plated layer 54defined by etch mask 60 that is spaced from plated through-hole 58.Routing line 66 is an unetched portion of conductive layer 30 and platedlayer 54 defined by etch mask 60 that is adjacent to and extendslaterally from and electrically connects plated through-hole 58 and pad64. Cap 68 is an unetched portion of conductive layer 30 and platedlayer 54 defined by etch mask 60 that is adjacent to and extendslaterally from and is thermally connected to post 24. Pad 64 has athickness of 80 microns (60+20). Cap 68 has a thickness of 20 micronswhere it is adjacent to post 24 and a thickness of 80 microns (60+20)where it is closest to pad 64. Thus, pad 64 and cap 68 contact andextend above adhesive 34, have the same thickness where they are closestto one another, have different thickness where cap 68 is adjacent topost 24 and are spaced from and coplanar with one another.

Conductive layer 32 and plated layer 56 as etched include terminal 70and cap 72. Terminal 70 and cap 72 are unetched portions of conductivelayer 32 and plated layer 56 defined by etch mask 62. Thus, conductivelayer 32 and plated layer 56 are a patterned layer that includesterminal 70 and cap 72.

Terminal 70 is an unetched portion of conductive layer 32 and platedlayer 56 defined by etch mask 62 that is adjacent to and extendslaterally from and is electrically connected to plated through-hole 58.Cap 72 is an unetched portion of conductive layer 32 and plated layer 56defined by etch mask 62 that is adjacent to and extends laterally beyondand is thermally connected to post 26. Terminal 70 has a thickness of 80microns (60+20). Cap 72 has a thickness of 20 microns where it isadjacent to post 26 and a thickness of 80 microns (60+20) where it isclosest to terminal 70. Thus, terminal 70 and cap 72 contact and extendbelow adhesive 36, have the same thickness where they are closest to oneanother, have different thickness where terminal 70 is adjacent to post26 and are spaced from and coplanar with one another.

Conductive trace 74 is provided by plated through-hole 58, pad 64,routing line 66 and terminal 70. Similarly, an electrically conductivepath between pad 64 and terminal 70 is plated through-hole 58 androuting line 66.

Heat spreader 76 is provided by posts 24 and 26, base 28 and caps 68 and72. Post 24 and base 28 are integral with one another and post 26 andbase 28 are integral with one another. Post 24 is sandwiched betweenbase 28 and cap 68 and post 26 is sandwiched between base 28 and cap 72.Cap 68 is above and adjacent to and covers in the upward direction andextends laterally in the lateral directions from the top of post 24 andis positioned so that post 24 is centrally located within its periphery.Likewise, cap 72 is below and adjacent to and covers in the downwarddirection and extends laterally in the lateral directions from thebottom of post 26 and is positioned so that post 26 is centrally locatedwithin its periphery. Furthermore, posts 24 and 26 are axially alignedwith and minor images of one another, caps 68 and 72 are axially alignedwith but not mirror images of one another and posts 24 and 26 and cap 68are located within the periphery of cap 72.

Heat spreader 76 is essentially a heat slug with an upper pedestal (post24), lower pedestal (post 26), upper wings that extend laterally fromthe upper pedestal (cap 68), lower wings that extend laterally from thelower pedestal (cap 72) and middle wings that extend laterally from theupper and lower pedestals (base 28).

FIG. 6P is a cross-sectional view of the structure with plated contacts78 formed on conductive trace 74 and heat spreader 76.

Plated contacts 78 are thin spot plated metal coatings that contact theexposed copper surfaces. Thus, plated contacts 78 contact platedthrough-hole 58, pad 64, routing line 66 and cap 68 and cover them inthe upward direction and contact plated through-hole 58, terminal 70 andcap 72 and cover them in the downward direction. For instance, a nickellayer is electrolessly plated on the exposed copper surfaces, and then asilver layer is electrolessly plated on the nickel layer. The buriednickel layer has a thickness of 3 microns, the silver surface layer hasa thickness of 0.5 microns, and plated contacts 78 have a thickness of3.5 microns.

Pad 64, cap 68, terminal 70 and cap 72 treated with plated contacts 78as a surface finish have several advantages. The buried nickel layerprovides the primary mechanical and electrical and/or thermalconnection, and the silver surface layer provides a wettable surface tofacilitate solder reflow and accommodates a solder joint and a wirebond. Plated contacts 78 also protect conductive trace 74 and heatspreader 76 from corrosion. Plated contacts 78 can include a widevariety of metals to accommodate the external connection media. Forinstance, a gold surface layer can be plated on a buried nickel layer ora nickel surface layer alone can be employed.

Conductive trace 74 and heat spreader 76 treated with plated contacts 78are shown as single layers for convenience of illustration. The boundary(not shown) in conductive trace 74 with plated contacts 78 and in heatspreader 76 with plated contacts 78 occurs at the copper/nickelinterface.

At this stage, the manufacture of thermal board 90 can be consideredcomplete.

FIGS. 6Q, 6R and 6S are cross-sectional, top and bottom views,respectively, of thermal board 90 after it is detached at peripheraledges along cut lines from a support frame and/or adjacent thermalboards in a batch.

Thermal board 90 includes adhesives 34 and 36, insulative filler 46,conductive trace 74 and heat spreader 76. Conductive trace 74 includesplated through-hole 58, pad 64, routing line 66 and terminal 70. Heatspreader 76 includes posts 24 and 26, base 28 and caps 68 and 72.

Post 24 extends into and remains centrally located within opening 34Aand remains centrally located within the peripheries of base 28,adhesives 34 and 36 and caps 68 and 72. Post 24 retains its cut-offconical shape with tapered sidewalls in which its diameter decreases asit extends upwardly from base 28 to its flat circular top adjacent tocap 68. Post 24 is also coplanar with adhesive 34 at their tops at cap68 and at their bottoms at base 28.

Post 26 extends into and remains centrally located within opening 36Aand remains centrally located within the peripheries of base 28,adhesives 34 and 36 and caps 68 and 72. Post 26 retains its cut-offconical shape with tapered sidewalls in which its diameter decreases asit extends downwardly from base 28 to its flat circular bottom adjacentto cap 72. Post 26 is also coplanar with adhesive 36 at their tops atbase 28 and at their bottoms at cap 72.

Base 28 is located below post 24 and covers post 24 in the downwarddirection, is located above post 26 and covers post 26 in the upwarddirection and extends laterally from posts 24 and 26 to the peripheraledges of thermal board 90. Base 28 remains sandwiched between posts 24and 26, adhesives 34 and 36 and caps 68 and 72 and provides mechanicalsupport for adhesives 34 and 36 and conductive trace 74. Furthermore,base 28 is thicker than pad 64, routing line 66, cap 68, terminal 70 andcap 72.

Adhesive 34 contacts and is sandwiched between post 24 and insulativefiller 46, contacts and is sandwiched between base 28 and pad 64,contacts and is sandwiched between base 28 and routing line 66, contactsand is sandwiched between base 28 and cap 68 and is spaced from post 26,adhesive 36, terminal 70 and cap 72. Adhesive 34 also extends laterallyfrom post 24 beyond and overlaps terminal 70, covers base 28 outside theperiphery of post 24 in the upward direction, covers cap 68 outside theperiphery of post 24 in the downward direction, covers and surroundspost 24 in the lateral directions and is solidified.

Adhesive 36 contacts and is sandwiched between post 26 and insulativefiller 46, contacts and is sandwiched between base 28 and terminal 70,contacts and is sandwiched between base 28 and cap 72 and is spaced frompost 24, adhesive 34, pad 64, routing line 66 and cap 68. Adhesive 36also extends laterally from post 26 beyond and overlaps terminal 70,covers base 28 outside the periphery of post 26 in the downwarddirection, covers cap 72 outside the periphery of post 26 in the upwarddirection, covers and surrounds post 26 in the lateral directions and issolidified.

Adhesive 34 alone can intersect an imaginary horizontal line betweenpost 24 and insulative filler 46, an imaginary vertical line betweenbase 28 and pad 64, an imaginary vertical line between base 28 androuting line 66 and an imaginary vertical line between base 28 and cap68. Thus, an imaginary horizontal line exists that intersects onlyadhesive 34 as the line extends from post 24 to insulative filler 46, animaginary vertical line exists that intersects only adhesive 34 as theline extends from base 28 to pad 64 and so on.

Adhesive 36 alone can intersect an imaginary horizontal line betweenpost 26 and insulative filler 46, an imaginary vertical line betweenbase 28 and terminal 70 and an imaginary vertical line between base 28and cap 72. Thus, an imaginary horizontal line exists that intersectsonly adhesive 36 as the line extends from post 26 to insulative filler46, an imaginary vertical line exists that intersects only adhesive 36as the line extends from base 28 to terminal 70 and so on.

Insulative filler 46 contacts base 28, adhesives 34 and 36, routing line66 and terminal 70 in outer hole 44, is spaced from posts 24 and 26,extends through base 28 and adhesives 34 and 36 and extends into but notthrough routing line 66 and terminal 70.

Plated through-hole 58 extends through base 28 and adhesives 34 and 36in inner hole 50. Plated through-hole 58 also contacts insulative filler46, is spaced from base 28 and adhesives 34 and 36 by insulative filler46 and is electrically isolated from base 28 by insulative filler 46.Plated through-hole 58 also retains its tubular shape with straightvertical inner and outer sidewalls in which its diameter is constant asit extends vertically from routing line 66 to terminal 70.

Pad 64 and cap 68 have the same thickness where they are closest to oneanother, have different thickness where cap 68 is adjacent to post 24,contact and extend above adhesive 34 and are coplanar with one anotherabove adhesive 34 at a top surface that faces in the upward direction.

Terminal 70 and cap 72 have the same thickness where they are closest toone another, have different thickness where cap 72 is adjacent to post26, contact and extend below adhesive 36 and are coplanar with oneanother below adhesive 36 at a bottom surface that faces in the downwarddirection.

Base 28 and adhesives 34 and 36 extend to straight vertical peripheraledges of thermal board 90 after it is detached or singulated from abatch of identical simultaneously manufactured thermal boards.

Pad 64 is customized as an electrical interface for a semiconductordevice such as an LED chip that is subsequently mounted on cap 68,terminal 70 is customized as an electrical interface for the next levelassembly such as a solderable electrical contact from a printed circuitboard, cap 68 is customized as a thermal interface for the semiconductordevice, and cap 72 is customized as a thermal interface for the nextlevel assembly such as the printed circuit board or a heat sink for anelectronic device.

Pad 64 and terminal 70 are horizontally and vertically offset from oneanother and exposed at the top and bottom surfaces, respectively, ofthermal board 90, thereby providing horizontal and vertical signalrouting between the semiconductor device and the next level assembly.

Conductive trace 74 provides horizontal (fan-out) routing from pad 64 toplated through-hole 58 by routing line 66 and vertical (top to bottom)routing from pad 64 to terminal 70 by plated through-hole 58. Conductivetrace 74 is not limited to this configuration. For instance, pad 64 canbe electrically connected to plated through-hole 58 without a routingline above adhesive 34 as defined by etch mask 60, and terminal 70 canbe electrically connected to plated through-hole 58 by a routing linebelow adhesive 36 as defined by etch mask 62. Pad 64 or routing line 66can be electrically connected to terminal 70 by separate platedthrough-holes 58 in separate electrically conductive paths. Furthermore,the electrically conductive path can include vias that extend throughadhesives 34 and/or 36 and routing lines (above and/or below adhesives34 and/or 36) as well as passive components such as resistors andcapacitors mounted on additional pads.

Conductive trace 74 is shown in cross-section as a continuous circuittrace for convenience of illustration. However, conductive trace 74 canprovide horizontal signal routing in both the X and Y directions. Thatis, pad 64 and terminal 70 can be laterally offset from one another inthe X and Y directions. Furthermore, plated through-hole 58 can belocated between pad 64 and cap 68, between terminal 70 and cap 72 or ata corner or peripheral edge of thermal board 90.

Conductive trace 74 and heat spreader 76 remain spaced from one another.As a result, conductive trace 74 and heat spreader 76 are mechanicallyattached and electrically isolated from one another.

Heat spreader 76 provides heat spreading and heat dissipation from asemiconductor device that is subsequently mounted on cap 68 to the nextlevel assembly that thermal board 90 is subsequently mounted on. Thesemiconductor device generates heat that flows into cap 68, from cap 68into post 24, through post 24 into base 28, through base 28 into post 26and through post 26 into cap 72, where it is spread out relative to post24 and dissipated in the downward direction, for instance to anunderlying heat sink.

Posts 24 and 26 and base 28 are copper. Plated through-hole 58, pad 64,routing line 66, cap 68, terminal 70 and cap 72 arecopper/nickel/silver. Plated through-hole 58, pad 64, routing line 66,cap 68, terminal 70 and cap 72 consist of a silver surface layer, aburied copper core and a buried nickel layer that contacts and issandwiched between the silver surface layer and the buried copper core.Plated through-hole 58, pad 64, routing line 66, cap 68, terminal 70 andcap 72 are also primarily copper at the buried copper core. Platedcontacts 78 provide the silver surface layer and the buried nickel layerand various combinations of metal plate 10, conductive layers 30 and 32and plated metal 52 provide the buried copper core.

Conductive trace 74 includes a buried copper core shared by platedthrough-hole 58, pad 64, routing line 66 and terminal 70 and heatspreader 76 includes a buried copper core shared by posts 24 and 26,base 28 and caps 68 and 72. Furthermore, conductive trace 74 includes aplated contact 78 at plated through-hole 58, pad 64, routing line 66 andterminal 70 and heat spreader 76 includes a plated contact 78 at cap 68and spaced from posts 24 and 26 and base 28 and another plated contact78 at cap 72 and spaced from posts 24 and 26 and cap 68. Moreover,conductive trace 74 consists of copper/nickel/silver and is primarilycopper at the buried copper core and heat spreader 76 consists ofcopper/nickel/silver and is primarily copper at the buried copper core.

Thermal board 90 does not expose post 24, post 26 or base 28 in theupward or downward direction. Post 24 is shown in phantom in FIG. 6R andpost 26 is shown in phantom in FIG. 6S for convenience of illustration.

Thermal board 90 can include multiple conductive traces 74 with a platedthrough-hole 58, pad 64, routing line 66 and terminal 70. A singleconductive trace 74 is described and labeled for convenience ofillustration. In conductive traces 74, plated through-holes 58, pads 64and terminals 70 generally have similar shapes and sizes. For instance,some conductive traces 74 may be spaced and separated and electricallyisolated from one another whereas other conductive traces 74 canintersect or route to the same pad 64, routing line 66 or terminal 70and be electrically connected to one another. Likewise, some pads 64 mayreceive independent signals whereas other pads 64 share a common signal,power or ground.

Thermal board 90 can be adapted for an LED package with blue, green andred LED chips, with each LED chip including an anode and a cathode andeach LED package including a corresponding anode terminal and cathodeterminal. In this instance, thermal board 90 can include six pads 64 andfour terminals 70 so that each anode is routed from a separate pad 64 toa separate terminal 70 whereas each cathode is routed from a separatepad 64 to a common ground terminal 70.

A brief cleaning step can be applied to the structure at variousmanufacturing stages to remove oxides and debris that may be present onthe exposed metal. For instance, a brief oxygen plasma cleaning step canbe applied to the structure. Alternatively, a brief wet chemicalcleaning step using a solution containing potassium permanganate can beapplied to the structure. Likewise, the structure can be rinsed indistilled water to remove contaminants. The cleaning step cleans thedesired surfaces without appreciably affecting or damaging thestructure.

Advantageously, there is no plating bus or related circuitry that needbe disconnected or severed from conductive traces 74 after they areformed. A plating bus can be disconnected during the wet chemical etchthat forms pad 64, routing line 66 and cap 68.

Thermal board 90 can include registration holes (not shown) that aredrilled or sliced through base 28 and adhesives 34 and 36 so thatthermal board 90 can be positioned by inserting tooling pins through theregistration holes when it is subsequently mounted on an underlyingcarrier.

Thermal board 90 can accommodate multiple semiconductor devices ratherthan one with a single post 24 or multiple posts 24. Thus, multiplesemiconductor devices can be mounted on a single post 24 or separatesemiconductor devices can be mounted on separate posts 24.

Thermal board 90 with a single post 24 for multiple semiconductordevices can be accomplished by drilling additional holes to defineadditional plated through-holes 58, adjusting etch mask 60 to defineadditional pads 64 and routing lines 66 and adjusting etch mask 62 todefine additional terminals 70. The plated through-holes 58, pads 64,routing lines 66 and terminals 70 can be laterally repositioned toprovide a 2×2 array for four semiconductor devices. In addition, thetopography (lateral shape) can be adjusted for pads 64 and terminals 70.

Thermal board 90 with multiple posts 24 for multiple semiconductordevices can be accomplished by adjusting etch mask 16 to defineadditional posts 24, adjusting conductive layer 30 to include additionalapertures 30A, adjusting adhesive 34 to include additional openings 34A,drilling additional outer holes 44 and inner holes 50 to defineadditional plated through-holes 58, adjusting etch mask 60 to defineadditional pads 64, routing lines 66 and caps 68 and adjusting etch mask62 to define additional terminals 70. These elements can be laterallyrepositioned to provide a 2×2 array for four semiconductor devices. Inaddition, the topography (lateral shape) can be adjusted for posts 24,pads 64, routing lines 66, caps 68 and terminals 70. Furthermore, posts24 can overlap separate posts 26 or overlap a single post 26 as definedby etch mask 62. Likewise, posts 26 can overlap separate caps 72 orshare a single cap 72 as defined by etch mask 62.

FIGS. 7A, 7B and 7C are cross-sectional, top and bottom views,respectively, of a thermal board with a plated through-hole at aperipheral edge in accordance with an embodiment of the presentinvention.

In this embodiment, the plated through-hole is located at a peripheraledge where the thermal board is detached. For purposes of brevity, anydescription of thermal board 90 is incorporated herein insofar as thesame is applicable, and the same description need not be repeated.Likewise, elements of the thermal board similar to those in thermalboard 90 have corresponding reference numerals.

Thermal board 91 includes adhesives 34 and 36, insulative filler 46,conductive trace 74 and heat spreader 76. Conductive trace 74 includesplated through-hole 58, pad 64, routing line 66 and terminal 70. Heatspreader 76 includes posts 24 and 26, base 28 and caps 68 and 72.

Plated through-hole 58 is located at a peripheral edge of thermal board91 rather than spaced from the peripheral edges of thermal board 91. Asa result, thermal board 91 is more compact than thermal board 90.Furthermore, plated through-hole 58 has a semi-tubular shape with asemi-circular circumference rather than a tubular shape with a circularcircumference and adhesives 34 and 36 extend laterally from posts 24 and26 to but not beyond terminal 70.

Thermal board 91 can be manufactured in a manner similar to thermalboard 90 with suitable adjustments for plated through-hole 58. Forinstance, adhesive 36 is mounted on base 28, conductive layer 32 ismounted on adhesive 36, the structure is inverted, adhesive 34 ismounted on base 28 and conductive layer 30 is mounted on adhesive 34.Thereafter, heat and pressure are applied to flow and solidify adhesives34 and 36, outer hole 44 is drilled through base 28, conductive layers30 and 32 and adhesives 34 and 36, insulative filler 46 is depositedinto outer hole 44, grinding is applied to planarize the top and bottomsurfaces, inner hole 50 is drilled through insulative filler 46 and thenplated layers 54 and 56 and plated through-hole 58 are deposited on thestructure. Thereafter, conductive layer 30 and plated layer 54 areetched to form pad 64, routing line 66 and cap 68, conductive layer 32and plated layer 56 are etched to form terminal 70 and cap 72 and thenplated contacts 78 provide a surface finish for pad 64, cap 68, terminal70 and cap 72. Thereafter, base 28 and adhesives 34 and 36 are cut orcracked at the peripheral edges of thermal board 91 to detach it fromthe batch. As a result, a semi-tubular portion of plated through-hole 58is detached from the peripheral edge while another semi-tubular portionof plated through-hole 58 at the peripheral edge remains intact.

FIGS. 8A, 8B and 8C are cross-sectional, top and bottom views,respectively, of a thermal board with a pad and a first cap with thesame thickness and a terminal and a second cap with the same thicknessin accordance with an embodiment of the present invention.

In this embodiment, the pad and the first cap are above the firstadhesive and have the same thickness and the terminal and the second capare below the second adhesive and have the same thickness. For purposesof brevity, any description of thermal board 90 is incorporated hereininsofar as the same is applicable, and the same description need not berepeated. Likewise, elements of the thermal board similar to those inthermal board 90 have corresponding reference numerals.

Thermal board 92 includes adhesives 34 and 36, insulative filler 46,conductive trace 74 and heat spreader 76. Conductive trace 74 includesplated through-hole 58, pad 64, routing line 66 and terminal 70. Heatspreader 76 includes posts 24 and 26, base 28 and caps 68 and 72.

Pad 64 and cap 68 contact and are located above adhesive 34. Pad 64 andcap 68 also have the same thickness. Thus, pad 64 and cap 68 have thesame thickness not only where they are closest to one another but alsowhere cap 68 is adjacent to post 24.

Terminal 70 and cap 72 contact and are located below adhesive 36.Terminal 70 and cap 72 also have the same thickness. Thus, terminal 70and cap 72 have the same thickness not only where they are closest toone another but also where cap 72 is adjacent to post 26.

Thermal board 92 can be manufactured in a manner similar to thermalboard 90 with suitable adjustments for pad 64, routing line 66, cap 68,terminal 70 and cap 72. For instance, metal plate 10 is 300 microns(rather than 500 microns) and posts 24 and 26 have a height of 50microns (rather than 150 microns). Furthermore, adhesives 34 and 36 asprepregs have a thickness of 60 microns (rather than 100 microns).

Adhesive 36 is mounted on base 28, the structure is inverted andadhesive 34 is mounted on base 28. However, conductive layers 30 and 32are omitted. Furthermore, posts 24 and 26 extend into but not throughopenings 34A and 36A.

Thereafter, heat and pressure are applied to flow and solidify adhesives34 and 36. For instance, adhesives 34 and 36 can be disposed between topand bottom platens of a press. In addition, a top cull plate and topbuffer paper can be sandwiched between adhesive 34 and the top platen,and a bottom cull plate and bottom buffer paper can be sandwichedbetween adhesive 36 and the bottom platen. The stack includes the topplaten, top cull plate, top buffer paper, adhesive 34, base 28, adhesive36, bottom buffer paper, bottom cull plate and bottom platen indescending order. Thus, adhesive 34 contacts and is sandwiched betweenbase 28 and the top buffer paper and adhesive 36 contacts and issandwiched between base 28 and the bottom buffer paper.

The platens are heated and move towards one another, thereby applyingheat and pressure to adhesives 34 and 36. As the platen motion and heatcontinue, adhesive 34 between base 28 and the top platen is compressed,melted and flows into contact with post 24 and adhesive 36 between base28 and the bottom platen is compressed, melted and flows into contactwith post 26. Furthermore, adhesive 34 creates a thin coating on the topsurface of post 24 and adhesive 36 creates a thin coating on the bottomsurface of post 26. The platen motion is eventually blocked by posts 24and 26 and the platens become stationary but continue to apply heat tosolidify adhesives 34 and 36. Thereafter, the platens move away from oneanother and the structure is released from the press.

The top buffer paper provides a release sheet for adhesive 34 and thebottom buffer paper provides a release sheet for adhesive 36. As aresult, the top buffer paper is easily peeled off from adhesive 34without delaminating adhesive 34 and the bottom buffer paper is easilypeeled off adhesive 36 without delaminating adhesive 36 after adhesives34 and 36 are solidified. Moreover, adhesive 34 laminates only itself topost 24 and base 28 and adhesive 36 laminates only itself to post 26 andbase 28.

Thereafter, outer hole 44 is drilled through base 28 and adhesives 34and 36, insulative filler 46 is deposited into outer hole 44, grindingis applied to planarize the top and bottom surfaces, inner hole 50 isdrilled through insulative filler 46 and then plated layers 54 and 56and plated through-hole 58 are deposited on the structure. Thereafter,plated layer 54 alone is etched to form pad 64, routing line 66 and cap68, plated layer 56 alone is etched to form terminal 70 and cap 72 andthen plated contacts 78 provide a surface finish for pad 64, cap 68,terminal 70 and cap 72. Thereafter, base 28 and adhesives 34 and 36 arecut or cracked at the peripheral edges of thermal board 92 to detach itfrom the batch.

FIGS. 9A, 9B and 9C are cross-sectional, top and bottom views,respectively, of a thermal board with first and second dielectric layersin accordance with an embodiment of the present invention.

In this embodiment, a first dielectric layer is sandwiched between thepad and the first adhesive and a second dielectric layer is sandwichedbetween the terminal and the second adhesive. For purposes of brevity,any description of thermal board 90 is incorporated herein insofar asthe same is applicable, and the same description need not be repeated.Likewise, elements of the thermal board similar to those in thermalboard 90 have corresponding reference numerals.

Thermal board 94 includes adhesives 34 and 36, insulative filler 46,conductive trace 74, heat spreader 76 and dielectric layers 80 and 82.Conductive trace 74 includes plated through-hole 58, pad 64, routingline 66 and terminal 70. Heat spreader 76 includes posts 24 and 26, base28 and caps 68 and 72.

Pad 64, routing line 66 and cap 68 contact and extend above dielectriclayer 80. Cap 68 contacts adhesive 34 between post 24 and dielectriclayer 80 but pad 64 and routing line 66 are spaced from adhesive 34.Dielectric layer 80 contacts and is sandwiched between adhesive 34 andpad 64, between adhesive 34 and routing line 66 and between adhesive 34and cap 68 and is spaced from post 24 and base 28.

Terminal 70 and cap 72 contact and extend below dielectric layer 82. Cap72 contacts adhesive 36 between post 26 and dielectric layer 82 butterminal 70 is spaced from adhesive 36. Dielectric layer 82 contacts andis sandwiched between adhesive 36 and terminal 70 and between adhesive36 and cap 72 and is spaced from post 26 and base 28.

Holes 44 and 50, insulative filler 46 and plated through-hole 58 extendthrough dielectric layers 80 and 82. Likewise, insulative filler 46contacts dielectric layers 80 and 82 and plated through-hole 58 isspaced from dielectric layers 80 and 82.

Thermal board 94 can be manufactured in a manner similar to thermalboard 90 with suitable adjustments for dielectric layers 80 and 82. Forinstance, metal plate 10 is 600 microns (rather than 500 microns), posts24 and 26 have a height of 200 microns (rather than 150 microns),conductive layers 30 and 32 have a thickness of 30 microns (rather than80 microns) and dielectric layers 80 and 82 are electrically insulativeepoxy sheets with a thickness of 100 microns. Furthermore, conductivelayer 30 and dielectric layer 80 are attached to one another as a firstcopper/epoxy substrate, conductive layer 32 and dielectric layer 82 areattached to one another as a second copper/epoxy substrate, aperture 30Aextends through conductive layer 30 and dielectric layer 80 and aperture32A extends through conductive layer 32 and dielectric layer 82.

Adhesive 36 is mounted on base 28, conductive layer 32 and dielectriclayer 82 are mounted on adhesive 36, the structure is inverted, adhesive34 is mounted on base 28 and conductive layer 30 and dielectric layer 80are mounted on adhesive 34. As a result, conductive layer 30 is spacedfrom adhesive 34, conductive layer 32 is spaced from adhesive 36,dielectric layer 80 contacts and is sandwiched between conductive layer30 and adhesive 34 and dielectric layer 82 contacts and is sandwichedbetween conductive layer 32 and adhesive 36. Furthermore, adhesives 34and 36 are non-solidified and dielectric layers 80 and 82 aresolidified.

Thereafter, heat and pressure are applied to flow and solidify adhesives34 and 36, outer hole 44 is drilled through base 28, conductive layers30 and 32, adhesives 34 and 36 and dielectric layers 80 and 82,insulative filler 46 is deposited into outer hole 44, grinding isapplied to planarize the top and bottom surfaces, inner hole 50 isdrilled through insulative filler 46 and then plated layers 54 and 56and plated through-hole 58 are deposited on the structure. Thereafter,conductive layer 30 and plated layer 54 are etched to form pad 64,routing line 66 and cap 68, conductive layer 32 and plated layer 56 areetched to form terminal 70 and cap 72 and then plated contacts 78provide a surface finish for pad 64, cap 68, terminal 70 and cap 72.Thereafter, base 28, adhesives 34 and 36 and dielectric layers 80 and 82are cut or cracked at the peripheral edges of thermal board 94 to detachit from the batch.

FIGS. 10A, 10B and 10C are cross-sectional, top and bottom views,respectively, of a thermal board with a rim in accordance with anembodiment of the present invention.

In this embodiment, a rim is mounted on the top surface. For purposes ofbrevity, any description of thermal board 90 is incorporated hereininsofar as the same is applicable, and the same description need not berepeated. Likewise, elements of the thermal board similar to those inthermal board 90 have corresponding reference numerals.

Thermal board 96 includes adhesives 34 and 36, insulative filler 46,conductive trace 74, heat spreader 76 and rim 84. Conductive trace 74includes plated through-hole 58, pad 64, routing line 66 and terminal70. Heat spreader 76 includes posts 24 and 26, base 28 and caps 68 and72.

Rim 84 is a square shaped frame that contacts and extends above adhesive34. Post 24 and cap 68 are centrally located within the periphery of rim84. For instance, rim 84 has a height of 600 microns, a width (betweenits inner and outer sidewalls) of 1000 microns and is laterally spacedfrom cap 68 by 500 microns.

Rim 84 includes a solder mask, a laminate and an adhesive film shown asa single layer for convenience of illustration. The solder mask contactsand extends above the laminate and provides the top surface, theadhesive film contacts and extends below the laminate and provides thebottom surface, and the laminate contacts and is sandwiched between andlaminated to the solder mask and adhesive film. The solder mask,laminate and adhesive film are electrical insulators. For instance, thesolder mask has a thickness of 50 microns, the laminate has a thicknessof 500 microns, and the adhesive film has thickness of 100 microns.Thus, rim 84 has a height of 650 microns (50+500+100).

The laminate can be various dielectric films formed from numerousorganic and inorganic electrical insulators. For instance, the laminatecan be polyimide or FR-4 epoxy although other epoxies such aspolyfunctional and bismaleimide triazine (BT) are suitable.Alternatively, rim 84 can include a metal ring on the adhesive film.

Thermal board 96 can be manufactured in a manner similar to thermalboard 90 with suitable adjustments for rim 84. For instance, Forinstance, adhesive 36 is mounted on base 28, conductive layer 32 ismounted on adhesive 36, the structure is inverted, adhesive 34 ismounted on base 28 and conductive layer 30 is mounted on adhesive 34.Thereafter, heat and pressure are applied to flow and solidify adhesives34 and 36, outer hole 44 is drilled through base 28, conductive layers30 and 32 and adhesives 34 and 36, insulative filler 46 is depositedinto outer hole 44, grinding is applied to planarize the top and bottomsurfaces, inner hole 50 is drilled through insulative filler 46 and thenplated layers 54 and 56 and plated through-hole 58 are deposited on thestructure. Thereafter, conductive layer 30 and plated layer 54 areetched to form pad 64, routing line 66 and cap 68, conductive layer 32and plated layer 56 are etched to form terminal 70 and cap 72, then rim84 is mounted on adhesive 34 and then plated contacts 78 provide asurface finish for pad 64, cap 68, terminal 70 and cap 72. Thereafter,base 28 and adhesives 34 and 36 are cut or cracked at the peripheraledges of thermal board 96 to detach it from the batch.

FIGS. 11A, 11B and 11C are cross-sectional, top and bottom views,respectively, of a thermal board with first and second solder masks inaccordance with an embodiment of the present invention.

In this embodiment, first and second solder masks selectively expose theconductive trace and the heat spreader. For purposes of brevity, anydescription of thermal board 90 is incorporated herein insofar as thesame is applicable, and the same description need not be repeated.Likewise, elements of the thermal board similar to those in thermalboard 90 have corresponding reference numerals.

Thermal board 98 includes adhesives 34 and 36, insulative filler 46,conductive trace 74, heat spreader 76 and solder masks 86 and 88.Conductive trace 74 includes plated through-hole 58, pad 64, routingline 66 and terminal 70. Heat spreader 76 includes posts 24 and 26, base28 and caps 68 and 72.

Solder mask 86 is an electrically insulative layer that selectivelyexposes pad 64 and cap 68 in the upward direction and covers adhesive 34where it is otherwise exposed in the upward direction, and solder mask88 is an electrically insulative layer that selectively exposes terminal70 and cap 72 in the downward direction and covers adhesive 36 where itis otherwise exposed in the downward direction.

Thermal board 98 can be manufactured in a manner similar to thermalboard 90 with suitable adjustments for solder masks 86 and 88. Forinstance, adhesive 36 is mounted on base 28, conductive layer 32 ismounted on adhesive 36, the structure is inverted, adhesive 34 ismounted on base 28 and conductive layer 30 is mounted on adhesive 34.Thereafter, heat and pressure are applied to flow and solidify adhesives34 and 36, outer hole 44 is drilled through base 28, conductive layers30 and 32 and adhesives 34 and 36, insulative filler 46 is depositedinto outer hole 44, grinding is applied to planarize the top and bottomsurfaces, inner hole 50 is drilled through insulative filler 46 and thenplated layers 54 and 56 and plated through-hole 58 are deposited on thestructure. Thereafter, conductive layer 30 and plated layer 54 areetched to form pad 64, routing line 66 and cap 68 and conductive layer32 and plated layer 56 are etched to form terminal 70 and cap 72.

Thereafter, solder mask 86 is formed on the top surface and solder mask88 is formed on the bottom surface. Solder masks 86 and 88 are initiallya photoimageable liquid resin that is dispensed on the top and bottomsurfaces, respectively. Thereafter, solder masks 86 and 88 are patternedby selectively applying light through reticles (not shown) so that thesolder mask portions exposed to the light are rendered insoluble,applying a developer solution to remove the solder mask portions thatare unexposed to the light and remain soluble and then hard baking, asis conventional.

Thereafter, plated contacts 78 provide a surface finish for pad 64, cap68, terminal 70 and cap 72 and then base 28, adhesives 34 and 36 andsolder masks 86 and 88 are cut or cracked at the peripheral edges ofthermal board 98 to detach it from the batch.

FIGS. 12A, 12B and 12C are cross-sectional, top and bottom views,respectively, of a semiconductor chip assembly that includes a thermalboard, a semiconductor device and an encapsulant in accordance with anembodiment of the present invention.

In this embodiment, the semiconductor device is an LED chip that emitsblue light, is mounted on the first cap, is electrically connected tothe pad using a wire bond and is thermally connected to the first capusing a die attach. The semiconductor device is covered by acolor-shifting encapsulant that converts the blue light to white light.

Semiconductor chip assembly 100 includes thermal board 90, LED chip 102,wire bond 104, die attach 106 and encapsulant 108. LED chip 102 includestop surface 110, bottom surface 112 and bond pad 114. Top surface 110 isthe active surface and includes bond pad 114 and bottom surface 112 is athermal contact surface.

LED chip 102 is mounted on heat spreader 76, electrically connected toconductive trace 74 and thermally connected to heat spreader 76. Inparticular, LED chip 102 is mounted on cap 68 (and thus post 24),overlaps (and thus extends laterally within the peripheries of) posts 24and 26, base 28 and caps 68 and 72 but does not overlap (and thus isoutside the periphery of) conductive trace 74, is electrically connectedto pad 64 by wire bond 104 and is thermally connected to andmechanically attached to cap 68 by die attach 106.

For instance, wire bond 104 is bonded to and electrically connects pads64 and 114, thereby electrically connecting LED chip 102 to terminal 70.Die attach 106 contacts and is sandwiched between and thermally connectsand mechanically attaches cap 68 and thermal contact surface 112,thereby thermally connecting LED chip 102 to post 24, thereby thermallyconnecting LED chip 102 to base 28, thereby thermally connecting LEDchip 102 to post 26 and thereby thermally connecting LED chip 102 to cap72.

Encapsulant 108 is a solid adherent electrically insulativecolor-shifting protective enclosure that provides environmentalprotection such as moisture resistance and particle protection for LEDchip 102 and wire bond 104. Encapsulant 108 contacts adhesive 34, pad64, routing line 66, cap 68, LED chip 102, wire bond 104 and die attach106, is spaced from posts 24 and 26, base 28, adhesive 36, platedthrough-hole 58, terminal 70 and cap 72 and covers posts 24 and 26, pad64, cap 68, LED chip 102, wire bond 104 and die attach 106 in the upwarddirection. Encapsulant 108 is transparent for convenience ofillustration.

Pad 64 is spot plated with nickel/silver to bond well with wire bond104, thereby improving signal transfer from conductive trace 74 to LEDchip 102, and cap 68 is spot plated with nickel/silver to bond well withdie attach 106, thereby improving heat transfer from LED chip 102 toheat spreader 76. Cap 68 also provides a highly reflective surface whichreflects the light emitted towards the silver surface layer by LED chip102, thereby increasing light output in the upward direction.Furthermore, since cap 68 is shaped and sized to accommodate thermalcontact surface 112, post 24 is not and need not be shaped and sized toaccommodate thermal contact 112.

LED chip 102 includes a compound semiconductor that emits blue light,has high luminous efficiency and forms a p-n junction. Suitable compoundsemiconductors include gallium-nitride, gallium-arsenide,gallium-phosphide, gallium-arsenic-phosphide,gallium-aluminum-phosphide, gallium-aluminum-arsenide, indium-phosphideand indium-gallium-phosphide. LED chip 102 also has high light outputand generates considerable heat.

Encapsulant 108 includes transparent silicone and yellow phosphor. Forinstance, the silicone can be polysiloxane resin and the yellow phosphorcan be cerium-doped yttrium-aluminum-garnet (Ce:YAG) fluorescent powder.The yellow phosphor emits yellow light in response to blue light, andthe blue and yellow light mix to produce white light. As a result,encapsulant 108 converts the blue light emitted by LED chip 102 intowhite light and assembly 100 is a white light source. In addition,encapsulant 108 has a hemisphere dome shape which provides a convexrefractive surface that focuses the white light in the upward direction.

Semiconductor chip assembly 100 can be manufactured by mounting LED chip102 on cap 68 using die attach 106, then wire bonding pads 64 and 114and then forming encapsulant 108.

For instance, die attach 106 is initially a silver-filled epoxy pastewith high thermal conductivity that is selectively screen printed on cap68 and then LED chip 102 placed on the epoxy paste using a pick-up headand an automated pattern recognition system in step-and-repeat fashion.Thereafter, the epoxy paste is heated and hardened at a relatively lowtemperature such as 190° C. to form die attach 106. Next, wire bond 104is a gold wire that is thermosonically ball bonded to pads 64 and 114and then encapsulant 108 is molded on the structure.

LED chip 102 can be electrically connected to pad 64 by a wide varietyof connection media, thermally connected to and mechanically attached toheat spreader 76 by a wide variety of thermal adhesives and encapsulatedby a wide variety of encapsulants.

Semiconductor chip assembly 100 is a first-level single-chip package.

FIGS. 13A, 13B and 13C are cross-sectional, top and bottom views,respectively, of a semiconductor chip assembly that includes a thermalboard with a rim, a semiconductor device and a lid in accordance with anembodiment of the present invention.

In this embodiment, the lid is mounted on the rim and the encapsulant isomitted. For purposes of brevity, any description of assembly 100 isincorporated herein insofar as the same is applicable, and the samedescription need not be repeated. Likewise, elements of the assemblysimilar to those in assembly 100 have corresponding reference numeralsindexed at two-hundred rather than one-hundred. For instance, LED chip202 corresponds to LED chip 102, wire bond 204 corresponds to wire bond104, etc.

Semiconductor chip assembly 200 includes thermal board 96, LED chip 202,wire bond 204, die attach 206 and lid 216. LED chip 202 includes topsurface 210, bottom surface 212 and bond pad 214. Top surface 210 is theactive surface and includes bond pad 214 and bottom surface 212 is thethermal contact surface.

LED chip 202 is mounted on heat spreader 76, electrically connected toconductive trace 74 and thermally connected to heat spreader 76. Inparticular, LED chip 202 is mounted on cap 68, overlaps posts 24 and 26,base 28 and caps 68 and 72 but does not overlap conductive trace 74, iselectrically connected to pad 64 by wire bond 204 and is thermallyconnected to and mechanically attached to cap 68 by die attach 206.

Lid 216 is a glass sheet that is mounted on rim 84, thereby forming asealed enclosure for LED chip 202 and wire bond 204 in an air cavity.Furthermore, lid 216 is transparent and does not color-shift light.

LED chip 202 emits white light which in turn radiates through lid 216and assembly 200 is a white light source.

Semiconductor chip assembly 200 can be manufactured by mounting LED chip202 on cap 68 using die attach 206, then wire bonding pads 64 and 214and then mounting lid 216 on rim 84.

Semiconductor chip assembly 200 is a first-level single-chip package.

FIGS. 14A, 14B and 14C are cross-sectional, top and bottom views,respectively, of a semiconductor chip assembly that includes a thermalboard with solder masks and a semiconductor device with backsidecontacts in accordance with an embodiment of the present invention.

In this embodiment, the semiconductor device is an LED package ratherthan an LED chip. Furthermore, the semiconductor device is mounted onthe heat spreader and the conductive trace, overlaps the posts and theconductive trace, is electrically connected to the pad using a solderjoint and is thermally connected to the first cap using a solder joint.

Semiconductor chip assembly 300 includes thermal board 98, LED package302 and solder joints 304 and 306. LED package 302 includes LED chip308, submount 310, wire bond 312, electrical contact 314, thermalcontact 316 and encapsulant 318. LED chip 308 includes a bond pad (notshown) electrically connected to a via (not shown) in submount 310 bywire bond 312, thereby electrically connecting LED chip 308 toelectrical contact 314. LED chip 308 is mounted on and thermallyconnected to and mechanically attached to submount 310 by a die attach(not shown), thereby thermally connecting LED chip 308 to thermalcontact 316. Submount 310 is a ceramic block with low electricalconductivity and high thermal conductivity, and contacts 314 and 316 areplated on and protrude downwardly from the backside of submount 310.Furthermore, LED chip 308 is similar to LED chip 102, wire bond 312 issimilar to wire bond 104 and encapsulant 318 is similar to encapsulant108.

LED package 302 is mounted on conductive trace 74 and heat spreader 76,electrically connected to conductive trace 74 and thermally connected toheat spreader 76. In particular, LED package 302 is mounted on pad 64and cap 68 (and thus post 24 and adhesive 34), overlaps (and thusextends laterally within the peripheries of) posts 24 and 26, base 28,adhesives 34 and 36, pad 64 and caps 68 and 72 but does not overlap (andthus is outside the peripheries of) plated through-hole 58 and terminal70, is electrically connected to pad 64 by solder joint 304 and isthermally connected to cap 68 by solder joint 306.

For instance, solder joint 304 contacts and is sandwiched between andelectrically connects and mechanically attaches pad 64 and electricalcontact 314, thereby electrically connecting LED chip 308 to terminal70. Likewise, solder joint 306 contacts and is sandwiched between andthermally connects and mechanically attaches cap 68 and thermal contact316, thereby thermally connecting LED chip 308 to cap 72.

Pad 64 is spot plated with nickel/silver to bond well with solder joint304, thereby improving signal transfer from conductive trace 74 to LEDchip 308, and cap 68 is spot plated with nickel/silver to bond well withsolder joint 306, thereby improving heat transfer from LED chip 308 toheat spreader 76. Furthermore, since cap 68 is shaped and sized toaccommodate thermal contact 316, post 24 is not and need not be shapedand sized to accommodate thermal contact 316.

Semiconductor chip assembly 300 can be manufactured by depositing asolder material on pad 64 and cap 68, then placing contacts 314 and 316on the solder material over pad 64 and cap 68, respectively, and thenreflowing the solder material to provide solder joints 304 and 306.

For instance, solder paste is selectively screen printed on pad 64 andcap 68, then LED package 302 is positioned over thermal board 98 using apick-up head and an automated pattern recognition system instep-and-repeat fashion. The pick-up head places contacts 314 and 316 onthe solder paste over pad 64 and cap 68, respectively. Next, the solderpaste is heated and reflowed at a relatively low temperature such as190° C. and then the heat is removed and the solder paste cools andsolidifies to form hardened solder joints 304 and 306. Alternatively,solder balls are placed on pad 64 and cap 68, then contacts 314 and 316are placed on the solder balls over pad 64 and cap 68, respectively, andthen the solder balls are heated and reflowed to form solder joints 304and 306.

The solder material can be initially deposited on thermal board 98 orLED package 302 by plating or printing or placement techniques, thensandwiched between thermal board 98 and LED package 302 and thenreflowed. The solder material can also be deposited on terminal 70 andcap 72 if required for the next level assembly. Furthermore, aconductive adhesive such as silver-filled epoxy or other connectionmedia can be used instead of solder, and the connection media on pad 64,cap 68, terminal 70 and cap 72 need not be the same.

Semiconductor chip assembly 300 is a second-level single-chip module.

The semiconductor chip assemblies and thermal boards described above aremerely exemplary. Numerous other embodiments are contemplated. Inaddition, the embodiments described above can be mixed-and-matched withone another and with other embodiments depending on design andreliability considerations. For instance, the thermal board can includesingle-level conductive traces and multi-level conductive traces. Thethermal board can also include multiple first posts arranged in an arrayfor multiple semiconductor devices and additional conductive traces toaccommodate the additional semiconductor devices. The thermal board canalso include a solder mask that selectively exposes the pad and thefirst cap and a rim mounted on the solder mask. The semiconductor devicecan be flip-chip bonded to the pad and the first cap by solder jointsand cover the pad and the posts in the first vertical direction. Thesemiconductor device can be covered in the first vertical direction by atransparent, translucent or opaque encapsulant and/or a transparent,translucent or opaque lid. For instance, the semiconductor device can bean LED chip that emits blue light and is covered by a transparentencapsulant or lid so that the assembly is a blue light source or acolor-shifting encapsulant or lid so that the assembly is a green, redor white light source. Likewise, the semiconductor device can be an LEDpackage with multiple LED chips and the thermal board can includeadditional conductive traces to accommodate the additional LED chips.

The semiconductor device can share or not share the heat spreader withother semiconductor devices. For instance, a single semiconductor devicecan be mounted on the heat spreader. Alternatively, numeroussemiconductor devices can mounted on the heat spreader. For instance,four small chips in a 2×2 array can be attached to the first post andthe thermal board can include additional conductive traces to receiveand route additional wire bonds to the chips. This may be more costeffective than providing a miniature post for each chip.

The semiconductor chip can be optical or non-optical. For instance, thechip can be an LED, an IR detector, a solar cell, a microprocessor, acontroller, a DRAM or an RF power amplifier. Likewise, the semiconductorpackage can be an LED package or an RF module. Thus, the semiconductordevice can be a packaged or unpackaged optical or non-optical chip.Furthermore, the semiconductor device can be mechanically, electricallyand thermally connected to the thermal board using a wide variety ofconnection media including solder and electrically and/or thermallyconductive adhesive.

The heat spreader can provide rapid, efficient and essentially uniformheat spreading and dissipation for the semiconductor device to the nextlevel assembly without heat flow through the adhesives. As a result, theadhesives can have low thermal conductivity which drastically reducescost. The heat spreader can include posts and a base that are integralwith one another and caps that are metallurgically bonded and thermallyconnected to the posts, thereby enhancing reliability and reducing cost.The first cap can be coplanar with the pad, thereby facilitating theelectrical, thermal and mechanical connections with the semiconductordevice. Furthermore, the first cap can be customized for thesemiconductor device and the second cap can be customized for the nextlevel assembly, thereby enhancing the thermal connection from thesemiconductor device to the next level assembly. For instance, the firstcap can have a square or rectangular shape in a lateral plane with thesame or similar topography as the thermal contact of the semiconductordevice and the second cap can have a square or rectangular shape in alateral plane with the same or similar topography as a heat sink. In anycase, the heat spreader can be a wide variety of thermally conductivestructures.

The pad can be electrically connected to or isolated from the first cap.For instance, a routing line above the first adhesive can electricallyconnect the pad and the first cap, a routing line below the secondadhesive can electrically connect the terminal and the second cap, thebase can be adjacent to and electrically connected to the platedthrough-hole or the pad and the first cap can be merged. Thereafter, theterminal can be electrically connected to ground, thereby electricallyconnecting the first cap to ground.

The posts can be deposited on or integral with the base. The posts canbe integral with the base when they are a single-piece metal such ascopper or aluminum. The posts can also be integral with the base whenthey include a single-piece metal such as copper at their interface aswell as additional metal elsewhere such as a solder post portion spacedfrom the base and a copper post portion adjacent to the base. The postscan also be integral with the base when they share single-piece metalsat their interface such as a copper coating on a nickel buffer layer onan aluminum core.

The first post can include a flat top surface that is coplanar with thefirst adhesive. For instance, the first post can be coplanar with thefirst adhesive or the first post can be etched after the first adhesiveis solidified to provide a cavity in the first adhesive over the firstpost. The first post can also be selectively etched to provide a cavityin the first post. In any case, the semiconductor device can be mountedon the first post and located in the cavity, and the wire bond canextend from the semiconductor device in the cavity to the pad outsidethe cavity. In this instance, the semiconductor device can be an LEDchip and the cavity can focus the LED light in the first verticaldirection.

The base can provide mechanical support for the conductive trace and theadhesives. For instance, the base can prevent the conductive layers fromwarping during metal grinding, chip mounting, wire bonding andencapsulant molding.

The caps can be formed by numerous deposition techniques includingelectroplating, electroless plating, evaporating and sputtering as asingle layer or multiple layers after the adhesives are solidified. Thecaps can be the same metal as the posts or the surfaces of the posts.Furthermore, the caps can include or be spaced from the conductivelayers. In any case, the first cap extends from the first post in thefirst vertical and lateral directions and the second cap extends fromthe second post in the second vertical and lateral directions.

The adhesives can provide a robust mechanical bond between the heatspreader and the conductive trace. For instance, the adhesives canextend laterally from the respective posts beyond the conductive traceto the peripheral edges of the assembly. The adhesives can also bevoid-free with consistent bond lines. The adhesives can also absorbthermal expansion mismatch between the heat spreader and the conductivetrace. The adhesives can also be the same material as or a differentmaterial than the dielectric layers. Furthermore, the adhesives can be alow cost dielectric that need not have high thermal conductivity.Moreover, the adhesives are not prone to delamination.

The adhesives thickness can be adjusted so that the adhesivesessentially fill the respective gaps and the adhesives are withinstructure once they are solidified and/or grinded. For instance, theoptimal prepreg thickness can be established through trial and error.

The first conductive layer alone can be mounted on the first adhesive.For instance, the first aperture can be formed in the first conductivelayer and then the first conductive layer can be mounted on the firstadhesive so that the first conductive layer contacts the first adhesiveand is exposed in the first vertical direction and the first postextends into and is exposed in the first vertical direction by the firstaperture. In this instance, the first conductive layer can have athickness of 80 to 150 microns which is thick enough to handle withoutwarping and wobbling yet thin enough to pattern without excessiveetching.

The second conductive layer alone can be mounted on the second adhesive.For instance, the second aperture can be formed in the second conductivelayer and then the second conductive layer can be mounted on the secondadhesive so that the second conductive layer contacts the secondadhesive and is exposed in the second vertical direction and the secondpost extends into and is exposed in the second vertical direction by thesecond aperture. In this instance, the second conductive layer can havea thickness of 80 to 150 microns which is thick enough to handle withoutwarping and wobbling yet thin enough to pattern without excessiveetching.

The first conductive layer and the first dielectric layer can be mountedon the first adhesive. For instance, the first conductive layer can beprovided on the first dielectric layer, then the first aperture can beformed in the first conductive layer and the first dielectric layer, andthen the first conductive layer and the first dielectric layer can bemounted on the first adhesive so that the first conductive layer isexposed in the first vertical direction, the first dielectric layercontacts and is sandwiched between and separates the first conductivelayer and the first adhesive and the first post extends into and isexposed in the first vertical direction by the first aperture. In thisinstance, the first conductive layer can have a thickness of 10 to 50microns such as 30 microns which is thick enough for reliable signaltransfer yet thin enough to reduce weight and cost. Furthermore, thefirst dielectric layer is a permanent part of the thermal board.

The second conductive layer and the second dielectric layer can bemounted on the second adhesive. For instance, the second conductivelayer can be provided on the second dielectric layer, then the secondaperture can be formed in the second conductive layer and the seconddielectric layer, and then the second conductive layer and the seconddielectric layer can be mounted on the second adhesive so that thesecond conductive layer is exposed in the second vertical direction, thesecond dielectric layer contacts and is sandwiched between and separatesthe second conductive layer and the second adhesive and the second postextends into and is exposed in the second vertical direction by thesecond aperture. In this instance, the second conductive layer can havea thickness of 10 to 50 microns such as 30 microns which is thick enoughfor reliable signal transfer yet thin enough to reduce weight and cost.Furthermore, the second dielectric layer is a permanent part of thethermal board.

The first conductive layer and a first carrier can be mounted on thefirst adhesive. For instance, the first conductive layer can be attachedto a first carrier such biaxially-oriented polyethylene terephthalatepolyester (Mylar) by a thin film, then the first aperture can be formedin the first conductive layer but not the first carrier, then the firstconductive layer and the first carrier can be mounted on the firstadhesive so that the first carrier covers the first conductive layer andis exposed in the first vertical direction, the thin film contacts andis sandwiched between the first carrier and the first conductive layer,the first conductive layer contacts and is sandwiched between the thinfilm and the first adhesive, and the first post is aligned with thefirst aperture and covered in the first vertical direction by the firstcarrier. After the first adhesive is solidified, the thin film can bedecomposed by UV light so that the first carrier can be peeled off thefirst conductive layer, thereby exposing the first conductive layer inthe first vertical direction, and then the first conductive layer can begrinded and patterned for the pad and the first cap. In this instance,the first conductive layer can have a thickness of 10 to 50 microns suchas 30 microns which is thick enough for reliable signal transfer yetthin enough to reduce weight and cost, and the first carrier can have athickness of 300 to 500 microns which is thick enough to handle withoutwarping and wobbling yet thin enough to reduce weight and cost.Furthermore, the first carrier is a temporary fixture and not apermanent part of the thermal board.

The second conductive layer and a second carrier can be mounted on thesecond adhesive in a similar manner.

The first substrate with the first conductive layer and the firstdielectric layer can be a low cost laminated structure that need nothave high thermal conductivity. The first substrate can include a singleconductive layer or multiple conductive layers. Furthermore, the firstsubstrate can be other electrical interconnects such as a ceramic boardor a printed circuit board and can include additional layers of embeddedcircuitry.

The second substrate with the second conductive layer and the seconddielectric layer can be a low cost laminated structure that need nothave high thermal conductivity. The second substrate can include asingle conductive layer or multiple conductive layers. Furthermore, thesecond substrate can be other electrical interconnects such as a ceramicboard or a printed circuit board and can include additional layers ofembedded circuitry.

The pad and the first cap can be coplanar at a first surface that facesin the first vertical direction, thereby enhancing solder joints betweenthe semiconductor device and the thermal board by controlling solderball collapse. Likewise, the terminal and the second cap can be coplanarat a second surface that faces in the second vertical direction, therebyenhancing solder joints between the thermal board and the next levelassembly by controlling solder ball collapse.

The pad and the terminal can have a wide variety of packaging formats asrequired by the semiconductor device and the next level assembly.

The pad and the terminal can be formed by numerous deposition techniquesincluding electroplating, electroless plating, evaporating andsputtering as a single layer or multiple layers, either before or afterthe conductive layers are mounted on the adhesives. For instance, thefirst conductive layer can be patterned on a first substrate to providethe pad before it is mounted on the first adhesive or after it isattached to the first post and the base by the first adhesive. Likewise,the second conductive layer can be patterned on a second substrate toprovide the terminal before it is mounted on the second adhesive orafter it is attached to the second post and the base by the secondadhesive.

The plated contact surface finish can be formed before or after the padand the terminal are formed. For instance, the plated contacts can bedeposited on the conductive layers before or after they are etched toform the pad, the terminal and the caps.

The rim can be reflective or non-reflective and transparent ornon-transparent. For instance, the rim can include a highly reflectivemetal such as silver or aluminum with a slanted inner surface whichreflects the light directed at it in the first vertical direction,thereby increasing light output in the first vertical direction.Likewise, the rim can include a transparent material such as glass or anon-reflective, non-transparent low cost material such as epoxy.Furthermore, a reflective rim can be used regardless of whether itcontacts or confines the encapsulant.

The encapsulant can be numerous transparent, translucent or opaquematerials and have various shapes and sizes. For instance, theencapsulant can be transparent silicone, epoxy or combinations thereof.Silicone has higher thermal and color-shifting stability than epoxy butalso higher cost and lower rigidity and adhesion than epoxy.

The lid can cover or replace the encapsulant. The lid can provideenvironmental protection such as moisture resistance and particleprotection for the chip and the wire bond in a sealed enclosure. The lidcan be numerous transparent, translucent or opaque materials and havevarious shapes and sizes. For instance, the lid can be transparent glassor silica.

A lens can cover or replace the encapsulant. The lens can provideenvironmental protection such as moisture resistance and particleprotection for the chip and the wire bond in a sealed enclosure. Thelens can also provide a convex refractive surface that focuses the lightin the first vertical direction. The lens can be numerous transparent,translucent or opaque materials and have various shapes and sizes. Forinstance, a glass lens with a hollow hemisphere dome can be mounted onthe thermal board and spaced from the encapsulant, or a plastic lenswith a solid hemisphere dome can be mounted on the encapsulant andspaced from the thermal board.

The conductive trace can include additional pads, terminals, platedthrough-holes, routing lines and vias as well as passive components andhave different configurations. The conductive trace can function as asignal, power or ground layer depending on the purpose of thecorresponding semiconductor device pad. The conductive trace can alsoinclude various conductive metals such as copper, gold, nickel, silver,palladium, tin, combinations thereof, and alloys thereof. The preferredcomposition will depend on the nature of the external connection mediaas well as design and reliability considerations. Furthermore, thoseskilled in the art will understand that in the context of asemiconductor chip assembly, the copper material can be pure elementalcopper but is typically a copper alloy that is mostly copper such ascopper-zirconium (99.9% copper), copper-silver-phosphorus-magnesium(99.7% copper) and copper-tin-iron-phosphorus (99.7% copper) to improvemechanical properties such as tensile strength and elongation.

The caps, conductive layers, plated layers, plated through-hole, platedcontacts, insulative filler, dielectric layers, solder masks and rim aregenerally desirable but may be omitted in some embodiments. Forinstance, if the openings and the apertures are punched rather thandrilled so that the first post is shaped and sized to accommodate athermal contact surface of the semiconductor device then the first capcan be omitted. Likewise, if a reflector is unnecessary then the rim canbe omitted.

The thermal board can include a thermal via that is spaced from theposts, extends through the base and the adhesives outside the openingsand the apertures and is adjacent to and thermally connects the base andthe caps to improve heat dissipation from the first cap to the secondcap and heat spreading in the second cap.

The assembly can provide horizontal or vertical single-level ormulti-level signal routing.

Horizontal single-level signal routing with the pad, the terminal andthe routing line above the dielectric layer is disclosed in U.S.application Ser. No. 12/616,773 filed Nov. 11, 2009 by Charles W. C. Linet al. entitled “Semiconductor Chip Assembly with Post/Base HeatSpreader and Substrate” which is incorporated by reference.

Horizontal single-level signal routing with the pad, the terminal andthe routing line above the adhesive and no dielectric layer is disclosedin U.S. application Ser. No. 12/616,775 filed Nov. 11, 2009 by CharlesW. C. Lin et al. entitled “Semiconductor Chip Assembly with Post/BaseHeat Spreader and Conductive Trace” which is incorporated by reference.

Horizontal multi-level signal routing with the pad and the terminalabove the dielectric layer electrically connected by first and secondvias through the dielectric layer and a routing line beneath thedielectric layer is disclosed in U.S. application Ser. No. 12/557,540filed Sep. 11, 2009 by Chia-Chung Wang et al. entitled “SemiconductorChip Assembly with Post/Base Heat Spreader and Horizontal SignalRouting” which is incorporated by reference.

Vertical multi-level signal routing with the pad above the dielectriclayer and the terminal beneath the adhesive electrically connected by afirst via through the dielectric layer, a routing line beneath thedielectric layer and a second via through the adhesive is disclosed inU.S. application Ser. No. 12/557,541 filed Sep. 11, 2009 by Chia-ChungWang et al. entitled “Semiconductor Chip Assembly with Post/Base HeatSpreader and Vertical Signal Routing” which is incorporated byreference.

The working format for the thermal board can be a single thermal boardor multiple thermal boards based on the manufacturing design. Forinstance, a single thermal board can be manufactured individually.Alternatively, numerous thermal boards can be simultaneously batchmanufactured using a single metal plate, a single first conductivelayer, a single second conductive layer, a single first adhesive, asingle second adhesive and a single plated metal and then separated fromone another. Likewise, numerous sets of heat spreaders and conductivetraces that are each dedicated to a single semiconductor device can besimultaneously batch manufactured for each thermal board in the batchusing a single metal plate, a single first conductive layer, a singlesecond conductive layer, a single first adhesive, a single secondadhesive and a single plated metal.

For example, multiple recesses can be etched in the metal plate to formmultiple first posts, multiple second posts and the base, then thenon-solidified second adhesive with second openings corresponding to thesecond posts can be mounted on the base such that each second postextends through a second opening, then the second conductive layer withsecond apertures corresponding to the second posts can be mounted on thesecond adhesive such that each second post extends through a secondopening into a second aperture, then the structure can be inverted, thenthe non-solidified first adhesive with first openings corresponding tothe first posts can be mounted on the base such that each first postextends through a first opening, then the first conductive layer withfirst apertures corresponding to the first posts can be mounted on thefirst adhesive such that each first post extends through a first openinginto a first aperture, then the conductive layers can be moved towardsone another by platens to force the first adhesive into the first gapsand the second adhesive into the second gaps, then the adhesives can becured and solidified, then multiple outer holes can be drilled throughthe conductive layers, the adhesives and the base, then the insulativefiller can be deposited into the outer holes, then the posts, theconductive layers, the adhesives and the insulative filler can begrinded to form first and second opposing lateral surfaces, then theinner holes can be drilled through the insulative filler in the outerholes, then the plated metal can be plated on the structure to form theplated layers and the plated through-holes in the inner holes, then thefirst conductive layer and the first plated layer can be etched to formthe first caps corresponding to the first posts and the pads and therouting lines corresponding to the plated through-holes, the secondconductive layer and the second plated layer can be etched to form thesecond caps corresponding to the second posts and the terminalscorresponding to the plated through-holes, then the plated contactsurface finish can be formed on the pads, the terminals and the caps andthen the base and the adhesives can be cut or cracked at the desiredlocations of the peripheral edges of the thermal boards, therebyseparating the individual thermal boards from one another.

The working format for the semiconductor chip assembly can be a singleassembly or multiple assemblies based on the manufacturing design. Forinstance, a single assembly can be manufactured individually.Alternatively, numerous assemblies can be simultaneously batchmanufactured before the thermal boards are separated from one another.Likewise, multiple semiconductor devices can be electrically, thermallyand mechanically connected to each thermal board in the batch.

For example, solder paste portions can be deposited on the pads and thefirst caps, then LED packages can be placed on the solder pasteportions, then the solder paste portions can be simultaneously heated,reflowed and hardened to provide the solder joints and then the thermalboards can be separated from one another.

As another example, die attach paste portions can be deposited on thefirst caps, then chips can be placed on the die attach paste portions,then the die attach paste portions can be simultaneously heated andhardened to provide the die attaches, then the chips can be wired bondedto the corresponding pads, then the encapsulants can be formed over thechips and the wire bonds and then the thermal boards can be separatedfrom one another.

The thermal boards can be detached from one another in a single step ormultiple steps. For instance, the thermal boards can be batchmanufactured as a panel, then the semiconductor devices can be mountedon the panel and then the semiconductor chip assemblies of the panel canbe detached from one another. Alternatively, the thermal boards can bebatch manufactured as a panel, then the thermal boards of the panel canbe singulated into strips of multiple thermal boards, then thesemiconductor devices can be mounted on the thermal boards of a stripand then the semiconductor chip assemblies of the strip can be detachedfrom one another. Furthermore, the thermal boards can be detached bymechanical sawing, laser sawing, cleaving or other suitable techniques.

The term “adjacent” refers to elements that are integral (single-piece)or in contact (not spaced or separated from) with one another. Forinstance, the posts are adjacent to the base regardless of whether theposts are formed additively or subtractively.

The term “overlap” refers to above and extending within a periphery ofan underlying element. Overlap includes extending inside and outside theperiphery or residing within the periphery. For instance, when the firstpost protrudes upward from the base and the second post protrudesdownward from the base, the semiconductor device overlaps the postssince an imaginary vertical line intersects the semiconductor device andthe posts, regardless of whether another element such as the first capor the die attach is between the semiconductor device and the posts andis intersected by the line, and regardless of whether another imaginaryvertical line intersects the posts but not the semiconductor device(outside the periphery of the semiconductor device). Likewise, the firstadhesive overlaps the base and is overlapped by the pad, the first postoverlaps and is within a periphery of the base and the base isoverlapped by the first post. Moreover, overlap is synonymous with overand overlapped by is synonymous with under or beneath.

The term “contact” refers to direct contact. For instance, theinsulative filler contacts the base and the adhesives but does notcontact the posts.

The term “cover” refers to complete coverage in the vertical and/orlateral directions. For instance, the base covers the first post in thesecond vertical direction but the first post does not cover the base inthe first vertical direction and the base covers the second post in thefirst vertical direction but the second post does not cover the base inthe second vertical direction.

The term “layer” refers to patterned and unpatterned layers. Forinstance, the conductive layers can be unpatterned blanket sheets whenthe adhesives are flowed and solidified, and the conductive layers canbe patterned circuits with spaced traces when the semiconductor deviceis mounted on the heat spreader. Furthermore, a layer can includestacked layers.

The term “pad” in conjunction with the conductive trace refers to aconnection region that is adapted to contact and/or bond to externalconnection media (such as solder or a wire bond) that electricallyconnects the conductive trace to the semiconductor device.

The term “terminal” in conjunction with the conductive trace refers to aconnection region that is adapted to contact and/or bond to externalconnection media (such as solder or a wire bond) that electricallyconnects the conductive trace to an external device (such as a PCB or awire thereto) associated with the next level assembly.

The term “plated through-hole” in conjunction with the conductive tracerefers to an electrical interconnect that is formed in a hole usingplating. For instance, the plated through-hole exists regardless ofwhether it remains intact in the hole and spaced from peripheral edgesof the assembly or is subsequently split or trimmed such that the holeis converted into a groove and the remaining portion is in the groove ata peripheral edge of the assembly.

The term “first cap” in conjunction with the heat spreader refers to acontact region that is adapted to contact and/or bond to externalconnection media (such as solder or thermally conductive adhesive) thatthermally connects the heat spreader to the semiconductor device.

The term “second cap” in conjunction with the heat spreader refers to acontact region that is adapted to contact and/or bond to externalconnection media (such as solder or thermally conductive adhesive) thatthermally connects the heat spreader to an external device (such as aPCB or a heat sink) associated with the next level assembly.

The terms “opening” and “aperture” and “hole” refer to a through-holeand are synonymous. For instance, the first post is exposed by the firstadhesive in the first vertical direction when it is inserted into thefirst opening in the first adhesive and the second post is exposed bythe second adhesive in the second vertical direction when it is insertedinto the second opening in the second adhesive.

The term “inserted” refers to relative motion between elements. Forinstance, the first post is inserted into the first aperture regardlessof whether the base is stationary and the first conductive layer movestowards the base, the first conductive layer is stationary and the basemoves towards the first conductive layer or the base and the firstconductive layer both approach the other. Furthermore, the first post isinserted (or extends) into the first aperture regardless of whether itgoes through (enters and exits) or does not go through (enters withoutexiting) the first aperture.

The phrase “move towards one another” also refers to relative motionbetween elements. For instance, the base and the first conductive layermove towards one another regardless of whether the base is stationaryand the first conductive layer moves towards the base, the firstconductive layer is stationary and the base moves towards the firstconductive layer or the base and the first conductive layer bothapproach the other.

The phrase “aligned with” refers to relative position between elements.For instance, the first post is aligned with the first aperture when thefirst adhesive is mounted on the base, the first conductive layer ismounted on the first adhesive, the first post is inserted into andaligned with the first opening and the first aperture is aligned withthe first opening regardless of whether the first post is inserted intoor spaced from the first aperture.

The phrase “mounted on” includes contact and non-contact with a singleor multiple support element(s). For instance, the semiconductor deviceis mounted on the heat spreader regardless of whether it contacts theheat spreader or is separated from the heat spreader by a die attach.

The term “above” refers to upward extension and includes adjacent andnon-adjacent elements as well as overlapping and non-overlappingelements. For instance, when the first post protrudes upward from thebase and the second post protrudes downward from the base, the firstpost extends above, is adjacent to, overlaps and protrudes from thebase. Likewise, the pad extends above the second post even though it isnot adjacent to or overlap the second post.

The term “below” refers to downward extension and includes adjacent andnon-adjacent elements as well as overlapping and non-overlappingelements. For instance, when the first post protrudes upward from thebase and the second post protrudes downward from the base, the baseextends below, is adjacent to and is overlapped by the first post.Likewise, the second post extends below the pad even though it is notadjacent to or overlapped by the pad.

The “first vertical direction” and “second vertical direction” do notdepend on the orientation of the semiconductor chip assembly (or thethermal board), as will be readily apparent to those skilled in the art.For instance, the first post extends vertically beyond the base in thefirst vertical direction and vertically beyond the first cap in thesecond vertical direction regardless of whether the assembly is invertedand/or mounted on a heat sink. Likewise, the base extends “laterally”from the posts in a lateral plane regardless of whether the assembly isinverted, rotated or slanted. Thus, the first and second verticaldirections are opposite one another and orthogonal to the lateraldirections, and laterally aligned elements are coplanar with one anotherat a lateral plane orthogonal to the first and second verticaldirections. Furthermore, the first vertical direction is the upwarddirection and the second vertical direction is the downward directionwhen the first post protrudes upward from the base and the second postprotrudes downward from the base, and the first vertical direction isthe downward direction and the second vertical direction is the upwarddirection when the first post protrudes downward from the base and thesecond post protrudes upward from the base.

The semiconductor chip assembly of the present invention has numerousadvantages. The assembly is reliable, inexpensive and well-suited forhigh volume manufacture. The assembly is especially well-suited for highpower semiconductor devices such as LED chips and large semiconductorchips as well as multiple semiconductor devices such as smallsemiconductor chips in arrays which generate considerable heat andrequire excellent heat dissipation in order to operate effectively andreliably.

The manufacturing process is highly versatile and permits a wide varietyof mature electrical, thermal and mechanical connection technologies tobe used in a unique and improved manner. The manufacturing process canalso be performed without expensive tooling. As a result, themanufacturing process significantly enhances throughput, yield,performance and cost effectiveness compared to conventional packagingtechniques. Moreover, the assembly is well-suited for copper chip andlead-free environmental requirements.

The embodiments described herein are exemplary and may simplify or omitelements or steps well-known to those skilled in the art to preventobscuring the present invention. Likewise, the drawings may omitduplicative or unnecessary elements and reference labels to improveclarity.

Various changes and modifications to the embodiments described hereinwill be apparent to those skilled in the art. For instance, thematerials, dimensions, shapes, sizes, steps and arrangement of stepsdescribed above are merely exemplary. Such changes, modifications andequivalents may be made without departing from the spirit and scope ofthe present invention as defined in the appended claims.

1. A semiconductor chip assembly, comprising: a semiconductor device; afirst adhesive that includes a first opening; a second adhesive thatincludes a second opening; a heat spreader that includes a first post, asecond post and a base, wherein (i) the first post is adjacent to thebase and extends vertically from the base in a first vertical direction,(ii) the second post is adjacent to the base and extends vertically fromthe base in a second vertical direction opposite the first verticaldirection and (iii) the base is sandwiched between the posts and extendslaterally from the posts in lateral directions orthogonal to thevertical directions; and a conductive trace that includes a pad, aterminal and an electrical interconnect, wherein an electricallyconductive path between the pad and the terminal includes the electricalinterconnect; wherein the semiconductor device is mounted on the firstpost, extends vertically beyond the base in the first verticaldirection, extends laterally within peripheries of the posts, iselectrically connected to the pad and thereby electrically connected tothe terminal and is thermally connected to the first post and therebythermally connected to the second post; wherein the first adhesiveextends vertically beyond the base in the first vertical direction,extends laterally from the first post to or beyond the terminal and issandwiched between the base and the pad; wherein the second adhesiveextends vertically beyond the base in the second vertical direction,extends laterally from the second post to or beyond the terminal and issandwiched between the base and the terminal; wherein the pad extendsvertically beyond the first post and the base in the first verticaldirection, the terminal extends vertically beyond the second post andthe base in the second vertical direction and the electricalinterconnect extends through the adhesives and the base and is spacedfrom and electrically isolated from the base; and wherein the first postextends into the first opening and extends vertically beyond a lateralsurface of the pad in the first vertical direction, the second postextends into the second opening and extends vertically beyond a lateralsurface of the terminal in the second vertical direction and the base issandwiched between the adhesives and covers the semiconductor device inthe second vertical direction.
 2. The assembly of claim 1, wherein thesemiconductor device is an LED chip.
 3. The assembly of claim 1, whereinthe semiconductor device is electrically connected to the pad using awire bond and is thermally connected to the first post using a dieattach.
 4. The assembly of claim 1, wherein the semiconductor device iselectrically connected to the pad using a first solder joint and isthermally connected to the first post using a second solder joint. 5.The assembly of claim 1, wherein the first adhesive contacts the firstpost and the base and is spaced from the second post and the secondadhesive contacts the second post and the base and is spaced from thefirst post.
 6. The assembly of claim 1, wherein the first adhesivecovers and surrounds the first post in the lateral directions and thesecond adhesive covers and surrounds the second post in the lateraldirections.
 7. The assembly of claim 1, wherein the first adhesiveextends to peripheral edges of the assembly and the second adhesiveextends to peripheral edges of the assembly.
 8. The assembly of claim 1,wherein the adhesives are spaced from one another.
 9. The assembly ofclaim 1, wherein the first post is integral with the base and the secondpost is integral with the base.
 10. The assembly of claim 1, wherein thefirst post has a diameter that decreases as it extends vertically fromthe base in the first vertical direction and the second post has adiameter that decreases as it extends vertically from the base in thesecond vertical direction.
 11. The assembly of claim 1, wherein the baseextends to peripheral edges of the assembly.
 12. The assembly of claim1, wherein the pad extends beyond the first adhesive in the firstvertical direction and the terminal extends beyond the second adhesivein the second vertical direction.
 13. The assembly of claim 1, whereinthe pad contacts the first adhesive and the terminal contacts the secondadhesive.
 14. The assembly of claim 1, wherein the pad is spaced fromthe first adhesive, the terminal is spaced from the second adhesive, afirst dielectric layer contacts and is sandwiched between the pad andthe first adhesive and is spaced from the first post and the base, asecond dielectric layer contacts and is sandwiched between the terminaland the second adhesive and is spaced from the second post and the base,the first post extends through the first dielectric layer, the secondpost extends through the second dielectric layer and the electricalinterconnect extends through the dielectric layers.
 15. The assembly ofclaim 1, wherein the electrical interconnect is a plated through-holethat extends through and is spaced from the adhesives and the base. 16.The assembly of claim 1, wherein the pad and the terminal are the samemetals.
 17. The assembly of claim 1, wherein the pad and the terminalinclude a gold, silver or nickel surface layer and a buried copper coreand are primarily copper and the base is copper.
 18. The assembly ofclaim 1, wherein the conductive trace includes a copper core shared bythe pad, the terminal and the electrical interconnect.
 19. The assemblyof claim 1, wherein the heat spreader includes a copper core shared bythe posts and the base.
 20. The assembly of claim 1, wherein theconductive trace includes a copper core shared by the pad, the terminaland the electrical interconnect and the heat spreader includes a coppercore shared by the posts and the base.
 21. A semiconductor chipassembly, comprising: a semiconductor device; a first adhesive thatincludes a first opening; a second adhesive that includes a secondopening; a heat spreader that includes a first post, a second post, afirst cap, a second cap and a base, wherein (i) the first post isadjacent to and integral with the base, extends vertically from the basein a first vertical direction and is sandwiched between the base and thefirst cap, (ii) the second post is adjacent to and integral with thebase, extends vertically from the base in a second vertical directionopposite the first vertical direction and is sandwiched between the baseand the second cap, (iii) the base is sandwiched between the posts andextends laterally from the posts in lateral directions orthogonal to thevertical directions, (iv) the first cap is adjacent to the first post,covers the first post in the first vertical direction and extendslaterally from the first post and (v) the second cap is adjacent to thesecond post, covers the second post in the second vertical direction andextends laterally from the second post; and a conductive trace thatincludes a pad, a terminal and an electrical interconnect, wherein anelectrically conductive path between the pad and the terminal includesthe electrical interconnect; wherein the semiconductor device is mountedon the first cap, extends vertically beyond the first cap in the firstvertical direction, extends laterally within peripheries of the postsand the caps, is electrically connected to the pad and therebyelectrically connected to the terminal and is thermally connected to thefirst cap and thereby thermally connected to the second cap; wherein thefirst adhesive contacts the first post and the base, is spaced from thesecond post, extends vertically beyond the base in the first verticaldirection, extends laterally from the first post to or beyond theterminal and is sandwiched between the base and the pad; wherein thesecond adhesive contacts the second post and the base, is spaced fromthe first post, extends vertically beyond the base in the secondvertical direction, extends laterally from the second post to or beyondthe terminal and is sandwiched between the base and the terminal;wherein the pad extends vertically beyond the first post and the firstadhesive in the first vertical direction, the terminal extendsvertically beyond the second post and the second adhesive in the secondvertical direction and the electrical interconnect extends through theadhesives and the base and is spaced from and electrically isolated fromthe base; and wherein the first post extends into the first opening andextends vertically beyond a lateral surface of the pad in the firstvertical direction, the second post extends into the second opening andextends vertically beyond a lateral surface of the terminal in thesecond vertical direction, the first cap extends vertically beyond thefirst adhesive in the first vertical direction, the second cap extendsvertically beyond the second adhesive in the second vertical directionand the base is sandwiched between the adhesives and covers thesemiconductor device in the second vertical direction.
 22. The assemblyof claim 21, wherein the semiconductor device is an LED chip, is locatedwithin the peripheries of the posts and the caps, is mounted on thefirst cap using a die attach, is electrically connected to the pad usinga wire bond and is thermally connected to the first cap using the dieattach.
 23. The assembly of claim 21, wherein the first adhesivecontacts the first cap and the second adhesive contacts the second cap.24. The assembly of claim 21, wherein the first adhesive covers andsurrounds the first post in the lateral directions and the secondadhesive covers and surrounds the second post in the lateral directions.25. The assembly of claim 21, wherein the first adhesive extends toperipheral edges of the assembly and the second adhesive extends toperipheral edges of the assembly.
 26. The assembly of claim 21, whereinthe first post has a diameter that decreases as it extends verticallyfrom the base to the first cap and the second post has a diameter thatdecreases as it extends vertically from the base to the second cap. 27.The assembly of claim 21, wherein the first post is coplanar with thefirst adhesive at the first cap and the second post is coplanar with thesecond adhesive at the second cap.
 28. The assembly of claim 21, whereinthe base extends to peripheral edges of the assembly.
 29. The assemblyof claim 21, wherein the pad contacts the first adhesive and theterminal contacts the second adhesive.
 30. The assembly of claim 21,wherein the pad is spaced from the first adhesive, the terminal isspaced from the second adhesive, a first dielectric layer contacts andis sandwiched between the pad and the first adhesive and is spaced fromthe first post and the base, a second dielectric layer contacts and issandwiched between the terminal and the second adhesive and is spacedfrom the second post and the base, the first post extends through thefirst dielectric layer, the second post extends through the seconddielectric layer and the electrical interconnect extends through thedielectric layers.
 31. The assembly of claim 21, wherein the electricalinterconnect is a plated through-hole that extends through and is spacedfrom the adhesives and the base.
 32. The assembly of claim 21, whereinthe pad and the first cap have the same thickness where closest to oneanother and are coplanar with one another at a first surface that facesin the first vertical direction.
 33. The assembly of claim 21, whereinthe pad and the first cap have the same thickness where closest to oneanother, have different thickness where the first cap is adjacent to thefirst post and are coplanar with one another at a first surface thatfaces in the first vertical direction.
 34. The assembly of claim 21,wherein the terminal and the second cap have the same thickness whereclosest to one another and are coplanar with one another at a secondsurface that faces in the second vertical direction.
 35. The assembly ofclaim 21, wherein the terminal and the second cap have the samethickness where closest to one another, have different thickness wherethe second cap is adjacent to the second post and are coplanar with oneanother at a second surface that faces in the second vertical direction.36. The assembly of claim 21, wherein the pad, the terminal and the capsare the same metals and the posts and the base are the same metal. 37.The assembly of claim 21, wherein the pad, the terminal and the capsinclude a gold, silver or nickel surface layer and a buried copper coreand are primarily copper and the posts and the base are copper.
 38. Theassembly of claim 21, wherein the conductive trace includes a coppercore shared by the pad, the terminal and the electrical interconnect.39. The assembly of claim 21, wherein the heat spreader includes acopper core shared by the posts, the base and the caps.
 40. The assemblyof claim 21, wherein the conductive trace includes a copper core sharedby the pad, the terminal and the electrical interconnect and the heatspreader includes a copper core shared by the posts, the base and thecaps.
 41. A semiconductor chip assembly, comprising: a semiconductordevice; a first adhesive that includes a first opening; a secondadhesive that includes a second opening; a heat spreader that includes afirst post, a second post, a first cap, a second cap and a base, wherein(i) the first post is adjacent to and integral with the base, extendsvertically from the base in a first vertical direction and is sandwichedbetween the base and the first cap, (ii) the second post is adjacent toand integral with the base, extends vertically from the base in a secondvertical direction opposite the first vertical direction and issandwiched between the base and the second cap, (iii) the base issandwiched between the posts and extends laterally from the posts andlaterally beyond the caps in lateral directions orthogonal to thevertical directions, (iv) the first cap is adjacent to the first post,covers the first post in the first vertical direction and extendslaterally from the first post and (v) the second cap is adjacent to thesecond post, covers the second post in the second vertical direction andextends laterally from the second post; and a conductive trace thatincludes a pad, a terminal and an electrical interconnect, wherein theelectrical interconnect is a plated through-hole and an electricallyconductive path between the pad and the terminal includes the electricalinterconnect; wherein the semiconductor device is mounted on the firstcap, extends vertically beyond the first cap in the first verticaldirection, extends laterally within peripheries of the posts and thecaps, is electrically connected to the pad and thereby electricallyconnected to the terminal and is thermally connected to the first capand thereby thermally connected to the second cap; wherein the firstadhesive contacts the first post and the base, is spaced from the secondpost, the second adhesive and the terminal, extends vertically beyondthe base in the first vertical direction, extends laterally from thefirst post to or beyond the terminal and is sandwiched between the baseand the pad; wherein the second adhesive contacts the second post andthe base, is spaced from the first post and the pad, extends verticallybeyond the base in the second vertical direction, extends laterally fromthe second post to or beyond the terminal and is sandwiched between thebase and the terminal; wherein the pad extends vertically beyond thefirst post and the first adhesive in the first vertical direction, theterminal extends vertically beyond the second post and the secondadhesive in the second vertical direction and the electricalinterconnect extends through and is spaced from the adhesives and thebase and is electrically isolated from the base; and wherein the firstpost extends into the first opening and extends vertically beyond alateral surface of the pad in the first vertical direction, the secondpost extends into the second opening and extends vertically beyond alateral surface of the terminal in the second vertical direction, thefirst cap extends vertically beyond the first adhesive in the firstvertical direction, the second cap extends vertically beyond the secondadhesive in the second vertical direction and the base is sandwichedbetween the adhesives, covers the semiconductor device in the secondvertical direction and extends to peripheral edges of the assembly. 42.The assembly of claim 41, wherein the semiconductor device is an LEDchip, is located within the peripheries of the posts and the caps, ismounted on the first cap using a die attach, is electrically connectedto the pad using a wire bond and is thermally connected to the first capusing the die attach.
 43. The assembly of claim 41, wherein the firstadhesive contacts the first cap, covers and surrounds the first post inthe lateral directions and extends to peripheral edges of the assemblyand the second adhesive contacts the second cap, covers and surroundsthe second post in the lateral directions and extends to peripheraledges of the assembly.
 44. The assembly of claim 41, wherein the firstpost has a diameter that decreases as it extends vertically from thebase to the first cap and the second post has a diameter that decreasesas it extends vertically from the base to the second cap.
 45. Theassembly of claim 41, wherein the first post is coplanar with the firstadhesive at the first cap and the second post is coplanar with thesecond adhesive at the second cap.
 46. The assembly of claim 41, whereinthe pad contacts the first adhesive and the terminal contacts the secondadhesive.
 47. The assembly of claim 41, wherein the pad is spaced fromthe first adhesive, the terminal is spaced from the second adhesive, afirst dielectric layer contacts and is sandwiched between the pad andthe first adhesive and is spaced from the first post and the base, asecond dielectric layer contacts and is sandwiched between the terminaland the second adhesive and is spaced from the second post and the base,the first post extends through the first dielectric layer, the secondpost extends through the second dielectric layer and the electricalinterconnect extends through the dielectric layers.
 48. The assembly ofclaim 41, wherein the pad and the first cap have the same thicknesswhere closest to one another, have different thickness where the firstcap is adjacent to the first post and are coplanar with one another at afirst surface that faces in the first vertical direction.
 49. Theassembly of claim 41, wherein the terminal and the second cap have thesame thickness where closest to one another, have different thicknesswhere the second cap is adjacent to the second post and are coplanarwith one another at a second surface that faces in the second verticaldirection.
 50. The assembly of claim 41, wherein the pad, the terminaland the caps are the same metals and include a gold, silver or nickelsurface layer and are primarily copper, the posts and the base arecopper, the electrical interconnect includes copper, the conductivetrace includes a copper core shared by the pad, the terminal and theelectrical interconnect and the heat spreader includes a copper coreshared by the posts, the base and the caps.